I understand your definition, but I don't agree with a part of it. You're saying that someone who THINKS homophobic thoughts is not to be called out for it because they are not ACTING on those thoughts by physically attacking others. I suppose I see your point there, people have a right to whatever they think or believe.
But you can hurt people without physically assaulting them. What if someone writes "Trans people are wrong. There's something wrong with them. I think they're disgusting." How do you suppose that would make a trans person, or someone who is confused about their gender, or someone who has a friend/family/loved one who is going through it, feel?
I appreciate that you're defending everyone having a right to their own opinion. I just hope you understand why phrases like the one I said above are really hurtful, and cause people to be outraged when they hear those opinions.
For the person who is expressing their opposition, it's just an opinion they are sharing. Their belief.
For the trans person, it's their entire identity and possibly their entire life. The stakes are very high! That's not an easy criticism to take, and say "oh well, that's someone's opinion."