Celebrim
Legend
The "I'm not comfortable with your PC being in love with my PC, stop/retcon it" position is "as far into the wrong as they can be" and "twisted and sick"?
No.
My feelings are more valid than your feelings is the beginning of something wrong. It gets 'as far into the wrong as they can be' when that tilt in to wrongness twists their perceptions, so that things start coming around backwards. For example, they start defining tolerance as not their own ability to live with the decisions of others, but other peoples ability to live with them. They start defining respect not as the condition of them treating other people compassionately, but of other people acquiesing to their demands. And so forth. They start demanding a unilateral relationship while believing that they now hold the moral high ground. They think that by going passive aggressive that they've absolved themselves, and woe betide anyone who dares to tresspass on their feelings - nevermind what anyone else feels.
Things moved past the, "I hate to squelsh everyone's fun, but I'm not comfortable with this line of play, can we tone it down or change it", when they became, "I won't comprimise at all and my feelings will trump the wishes of everyone else at the table." Stop looking at this one example in particular and look at the general case. There is no evil a person will not do when they tell themselves that they have been wronged.
Ultimately what I think we are moving toward in this argument where player A is wholly in the wrong and player B fully justified, is an argument that attempts to justify the same disrespect for others player A potentially has provided you only manifest it in a reactive or proactive way instead of an active one. But that isn't really consensual play, because its unilateral in how it views the flow of authority. You end up consigning the game to the hands of the person most easily offend and who most quickly becomes indignant, and telling them that they are morally justified in doing so.