There is a difference between attending an invalid mass and standing around outside while you wait for it to finish.
This is why some think you are trolling.
EVEN IF you held an extreme position on the Indult (all such priests are invalid, the "Masses" are mere simulations, etc.), it STILL wouldn't be a problem to merely stand around outside on the public street. You obviously aren't part of that church (error, travesty, compromise, etc.) or you'd be inside!
I guess we should never underestimate the insanity power of scruples...