It can always happen that someone disagrees with you. I know I can be strongly opinionated and therefore I can might be threatening, but I never have the intention to threaten people.
If it doesn't harm anybody, or if it is not making life difficult I would just agree to disagree and not go into a discussion with that person. Just say I disagree with you and a discussion will not go anywhere between us, so lets just respect each others opinion and agree to disagree.
It doesn't always work, but with me it was with my ex new girlfriend and she doesn't respect my opinion. She tries to ridicule me when we are in the same crowd of people (friends) even warn other people for my opinion and what I might do. She makes nasty remarks so just I can hear it too but in a way I cannot reply to it directly. To be more precise I am in favor of sterilizing dogs and she is not (I am not going into this discussion here, it's just an example). I decided to agree to disagree, but she several times made remarks like 'beware of her if she is offering to dog sit your dog, because she will probably chop off the balls'. And she is just joking then....
I hate her. And not because she is my ex girlfriend, my ex had a role in it too. I don't blame her. It is really s**t but these things happen. She used me, used my trust in her, I believed in her insecurity, she made promises... But as soon as she was secure enough, she skrewed me over. Banned me from a bicycle workshop (something I am quite interested in to get involved in and she knows this), demanded things, make fun of me and my opinions.
At the moment I just avoid her, because she is not worth wasting my energy on it and I have to avoid stress too (triggers black outs).
Basically agree to disagree only works I think if you respect each others differences and opinions.
If this is not the case, I don't know really. I am struggling with it myself. I don't know what is wise.