[Sabatier]

I have to respectfully disagree, though I see your point.
But I believe that if the pastor's sermon has become
an occasion of sin for me, it is appropriate to leave.
It is more disrespectful to the Lord to be steaming in
anger in church than to quietly leave.

[PMCarey]

I believe that if the pastor's sermon has become an occasion of sin for me, it is appropriate to leave.

That's an excellent point. Perhaps the best solution would be to leave at an appropriate time that causes the least amount of disruption and attention to one's self - and then to make sure to go to Mass at a different church that morning.