Law of being on-point (for lack of a better title)
A: Rantrantrant.
Comments: *agree*
B: I disagree, here's why. *bunch of valid reasons*
A: You're missing the point. *nitpicks every reason*
B: No, I understood you, I just don't agree.
A: ...You're MISSING my POINT!
B: Dude, whatever. *GTFOs*

To put it more eloquently: Accusing someone of "missing the point" just because they don't agree with you automatically loses the argument.

[If such a law already exists, disregard this post]