This is exactly what I do:
early morning, attend FSSP low mass.
late morning drive to protestant church - play the organ (a few hymns before the service, 3 hymns during, and an improvised interlude). This is paid job.
afternoon - temporarily filling in for injured organist at another church. 3 hymns.
There are other jobs you can do for pay, and by doing this job you're obviously attending a Protestant service. You did say yourself that you play hymns during their service. This wouldn't be possible if you weren't attending their service, even if you don't concede to any of their heresies. I'm sure you don't need me to tell you that doing so is wrong.
Depends. Some of the hymns are Catholic (i.e., Holy God we praise Thy Name, All Creatures of our God & King) - some are written by Protestants but are used by Catholic churches, others are just plain American "revivalist" songs that hardly pass for music.
Even if there are Catholic hymns being sung, you're still attending a Protestant service and contributing to the propagation and maintenance of a false religion by doing so.
Does this reasoning imply that we are not to play Mozart, or Bach, or Handel, or ____, etc? Hard to justify when they are playing Beethoven in SSPX seminary.
The difference between attending a Protestant service that has everything to do with Protestantism and listening to a musician play a piece that may or may not even have anything to do with religion whatsoever is like the difference between night and day.
I'm not worshiping with Protestants or using their "Protestant music" to worship.
But you are attending a Protestant service, which, as I've intimated before, is completely unacceptable. You have no way to get around this.
By the way what is meant by that anyhow, since many hymn tunes are used in Catholic churches by are secular or Protestant in origin. Among these, is the beautiful Holy Week hymn O Sacred Head now Wounded, which is of 16th century secular origin.
As I've said before, there is no excuse.
Like i've said: its a job!
There's more than 1 job out there that doesn't involve attending the worship services of heretics.
Please show how is participating in heresy. I can't catch heresy from just sitting in a Protestant church.
Why do you even need an example? Is the mere fact that you're contributing to the worship service of heretics not enough? You may not be "catching heresy" by being there but you certainly are giving your tacit approval of it by choosing to sit there and contributing to their service by playing music for them.
Plus some organist get $200 *cash* for 1 hr. I don't get paid nearly that much, but anywhere from $25 to $50 in cash (no taxes) for 1 hr and practically no physical exertion...is hard to find elsewhere.
Even if you were paid $1 million per second of your time, it is inexcusable for you to attend the worship services of heretics or to contribute to it in any way.
True but there are degrees to this. What type of defense you give is depend on what station you are in.
You are not in a situation to give any valid defense of your actions whatsoever, and you have not shown yourself to be in such a situation.