If you are eating less meat and moving towards being more vegetarian, then I have another idea on why this bothered you so much. When I was transitioning towards vegetarianism, I still cooked meat but was trying to keep it used as sparingly as possible. I would take a pound (or more) of hamburger and cook it with potatoes and carrots and celery and freeze it in several small freezer bags so that if someone wanted hamburger in something they could add a little and think they were getting more, but would also get their vegetables. Once I had cooked up some of that mixture and hadn't packaged it all up yet so it was still in pans on the stove, and someone came by and ended up staying for dinner, and I put some of the hamburger mixture in some pasta and served it for dinner, and she helped herself to about half of the meat in the pan too. It bothered me, because that wasn't what I had intended, and defeated the purpose I was going for. I didn't say anything, but it did irritate me.

I wonder if it might bother you (like it did/does me) when people consume large quantities of meat unnecessarily without thinking about it. Especially when it is in your home. I'm not judging this as good or bad, but wondering if it is something you can relate to, or that might be underlying your irritation.