The Church teaches that Jєωs will exist until the End of Days. It is also a sin to think or desire that Jєωs could disappear, for you would be doubting the Church's teaching that they will exist until the Second Coming.

This teaching qualifies as a hard teaching for me. For some a hard teaching is that non-Catholics don't get to heaven, so those of you who have developed a closeness to a non-Catholic who has died can't console yourself that they're in Heaven.

And yet the Church appears to have spoken in this regard. Jєωs will exist until the end of time, and it would qualify as a sin to think or want otherwise. There can be no good reason to not want what the Church wants.

There have been Catholics of ages past who were in favor of reducing Jєωs to chattel slavery. I guess that's the best scenario for which a Catholic can hope. Or quarantining them somewhere.

It is not a sin to desire that the Jєωs would disappear. That's preposterous. Desiring and praying for their conversion and an end to their evil can only be a good thing, even if we know it can't fully come true until the End of Days. It's like how we pray for peace and the conversion of non-believers. We know that there will always be war until the End Times, and we know that in the End Times there will be a Great Apostasy rather than a Great Conversion, so by your logic praying for those things is wrong since they cannot be. But it is never wrong to wish the world be a better, more virtuous place.
And reducing them to chattel slavery would be very unCatholic behaviour.

Obviously I don't mean that I don't desire that Jєωs cease to be Jєωs on an individual basis through sincere conversion to the Church. I don't know how you thought I meant that.

The Church teaches that the Jєωs will exist until the end of days, even though there will be some Jєωs who will cease to be Jєωs before that time.

St. Thomas Aquinas was in favor of reducing them to slavery.

The Jєωs (Hebrews) of the Old Testament are are not the same as the Jєωs post Christ's death on the Cross. The Jєωs post Christ's death on the Cross are the Pharisees and Scribes referred to as the Sons of Satan. Not many Jєωs converted to Christianity (number of canonized Jєωιѕн Saints speaks for itself) post Christ's crucifixion.

Thanks for you reply. Which Jєωs are being referred to as existing until the end times?

There have been Catholics of ages past who were in favor of reducing Jєωs to chattel slavery. I guess that's the best scenario for which a Catholic can hope. Or quarantining them somewhere.

St. Thomas Aquinas wrote:

"Jєωs by reason of their fault (killing Christ) are sentenced to perpetual servitude”

He also noticed that Jєωs seem to have nothing except what they acquired through the depravity of usury. I think this country, the United States of America, has been completely enslaved through that.

He also wrote "Jєωs of each sex in all Christian provinces, and all the time, should be distinguished from other people by some clothing".

The necessity of this distinction between Catholics and Jєωs was also taught via an Ecuмenical Council:  the Fourth Lateran Council promulgated by Pope Innocent III. This Council declared that: "Jєωs and Muslims of both sexes in every Christian province and at all times shall be marked off in the eyes of the public from other peoples through the character of their dress."

68. Jєωs appearing in public

A difference of dress distinguishes Jєωs or Saracens from Christians in some provinces, but in others a certain confusion has developed so that they are indistinguishable. Whence it sometimes happens that by mistake Christians join with Jєωιѕн or Saracen women, and Jєωs or Saracens with christian women. In order that the offence of such a damnable mixing may not spread further, under the excuse of a mistake of this kind, we decree that such persons of either sex, in every christian province and at all times, are to be distinguished in public from other people by the character of their dress — seeing moreover that this was enjoined upon them by Moses himself, as we read. They shall not appear in public at all on the days of lamentation and on passion Sunday; because some of them on such days, as we have heard, do not blush to parade in very ornate dress and are not afraid to mock Christians who are presenting a memorial of the most sacred passion and are displaying signs of grief. What we most strictly forbid however, is that they dare in any way to break out in derision of the Redeemer. We order secular princes to restrain with condign punishment those who do so presume, lest they dare to blaspheme in any way him who was crucified for us, since we ought not to ignore insults against him who blotted out our wrongdoings.

69. Jєωs not to hold public offices

It would be too absurd for a blasphemer of Christ to exercise power over Christians. We therefore renew in this canon, on account of the boldness of the offenders, what the council of Toledo providently decreed in this matter : we forbid Jєωs to be appointed to public offices, since under cover of them they are very hostile to Christians. If, however, anyone does commit such an office to them let him, after an admonition, be curbed by the provincial council, which we order to be held annually, by means of an appropriate sanction. Any official so appointed shall be denied commerce with Christians in business and in other matters until he has converted to the use of poor Christians, in accordance with the directions of the diocesan bishop, whatever he has obtained from Christians by reason of his office so acquired, and he shall surrender with shame the office which he irreverently assumed. We extend the same thing to pagans.

70. Jєωιѕн converts may not retain their old rite

Certain people who have come voluntarily to the waters of sacred baptism, as we learnt, do not wholly cast off the old person in order to put on the new more perfectly. For, in keeping remnants of their former rite, they upset the decorum of the christian religion by such a mixing. Since it is written, cursed is he who enters the land by two paths, and a garment that is woven from linen and wool together should not be put on, we therefore decree that such people shall be wholly prevented by the prelates of churches from observing their old rite, so that those who freely offered themselves to the christian religion may be kept to its observance by a salutary and necessary coercion. For it is a lesser evil not to know the Lord’s way than to go back on it after having known it.

http://www.papalencyclicals.net/councils/ecuм12-2.htm