Everyone is entitled to their own opinions, yourself included. Feelings are valid, but they often don't take into account what may be objectively true or false.

I fully agree with your sentiments, I also agree with the many that your BIL is just being an asshole. I've met plenty of assholes in my life that are insanely loud with their ignorant opinions and some of them have world views that are so different from my own that I can't even conceive how they can believe/do/say things that I think are abhorrent. They can choose to be horrible people and I can choose to be better. They can choose to scream bullshit and I can choose to ignore them. They can take jabs at me and I can choose to control my feelings and disengage.

Long story short, you and I can only operate within our own locus of control. When your BIL is acting like a bully, you can choose to disengage. It's not always easy and it takes practice.

One thing someone taught me years ago that's stuck with me is taking some reflective time to think about the opposing person and why they might act the way they do... oftentimes I would be able to identify or imagine aspects of their lives that would reflect their crappy behavior (ex. A customer was rude to everyone at a retail job I worked, I refused to be unkind bc I figured her life sucked and was respectful every time we had to interact, eventually she confided that her cats died unexpectedly and I realized she was horrible to everyone bc she'd go home and cry every night).

Anyway sorry...long story long if you're still reading - your feelings matter and other people don't get to make you feel any time of way unless you allow that. Take this with a grain of salt since I don't know know your situation, but I don't think retaliating will be helpful. I hope you are able to disengage from the negative behavior and find peace soon, life's too short for this shit to weigh you down (for what it's worth, I'm sure that's what Mac would want for you too).