In general, for most Catholics, you would be correct. But as I said, sometimes God has a few be an exception to the norm.
The reason I went was only because someone put the card to the place on my car windshield. The valuable things I took was the list of people on a "prayer list" at the location; I intend to enroll at least a few in perpetual Masses. I also gleaned some facts about the pastor and many in the congregation that I would not have obtained without an in-person conversation: that most of the people there were lapsed Catholics. Thus, the spiritual danger is far greater for the people there than if they were purely ignorant as more common Protestants are. The other purpose is most likely for me to see how the enemy conducts battle, and how much prep is need on my part. Very clearly, command of the Bible is one thing I have to correct. And I have to be well-versed in the King James to engage with these King James Only types even though it technically isn't Catholic.
I did not go to there at the exclusion of the obligation for Mass. It was parish Mass, different Parish Mass, Baptist guy, the 5pm Mass at "home Parish", then the 8pm "rock Mass" on that Sunday. I don't even "like" the Mass in the sentimental sense but yet I go.
The "wind" also work this way. At Christmas I went to the SSPX Mass. Mentioning that location a few weeks later got me banned from r/Catholicism on Reddit even though I mentioned two diocesan locations. Of course it had a purpose. This revived some of the old pro-trad inclinations I had in the past.
I must note that I have apparently been granted a great degree of immunity to "corruption". That is why I have already read the Satanic Bible and noted something. There is a continuum of compliance with Christ's mercy and forgiveness. The Satanism explicitly rejects Christ. But the majority of humanity "selectively enforces" mercy and forgiveness. But Christ's call to mercy and forgiveness is absolute, that even the worst, most hated of sinners...one must desire his salvation. God has made me spent a lot of money on books, some of it "intercepting" evil books by traitorous Catholics. Traitors like Charles E. Curran, Elizabeth A. Johnson, John T. Noonan. Noonan especially, was one of the most keen minds and great forces that was pro-contraception. Seeing Noonan's writings, I had to contemplate what fierce forces Paul VI was having to fight quietly and not seen from the public before Humane Vitae.
I must also mention I have gleaned a message from experiences that I'm not to die on my own terms, and probably not comfortably either.
On the one hand, studying false religions isn't a sin and learning more about how other Christian denominations think isn't a sin in itself. Otherwise we would have to conclude that theologians who fight heresies are sinning daily, which would be ludicrous.
On the other hand, the Sunday obligation is not negated by going to a false religion's worship. Moreover you aren't as "immune to corruption" as you think, the Devil loves to play such tricks on people to flatter their pride then pulls the rug from them.
Furthermore, it is doubtful whether you have solid basics on the Catholic faith in the first place. Studying false religions before having good knowledge of Catholicism renders you vulnerable to influence from false religions. It would at the very least be sinful because of imprudence.
Is there any benefit from what you're doing or is it only about satiating your curiosity?