Precisely. Why state it in the first place if you do not wish to engage in discussion? Why state "4e is videogamey" if all it is is a negative opinion that cannot be changed by evidence or discussion?
Is the point of posting something to a message board to engage in discussion? But, if your opinion cannot be changed, then you no longer want discussion, you only want vindication.
IOW if your point is so carved in stone that it cannot even be elaborated on, why bother in the first place? What purpose does it serve?
Why post it? For honesty & completeness. Vindication has nothing to do with it.
If someone asks me what I dislike about 4Ed, I'll give them an honest answer, and among the many things I could list, I will say that its too videogamey.
Now, some of the things I list will be about mechanic/fluff changes that I disagree with for truly debatable reasons.
However, a pure gut feel that the game is too videogamey for me is both 1) a very real aspect of the game I dislike, thus a valid thing for me to list among my dislikes and 2) an emotional/perceptual assessment that is essentially inarguable; generally, it is not accessible to alteration through debate.
The ones seeking vindication are those who want to debate perceptions and then say "See, you were wrong about this and I'm right!"
Say, for instance someone had said "I dislike 4Ed because its too dead-grampaw-y." and you asked for them to explain.
And they post some horror story about their dead grampaw and its convoluted and- to you- only tenuous connection to the deceased, what good will your posts about "You know, 4Ed isn't really connected to your dead grampaw, and here's why...", what kind of reaction do you expect to get? Do you think you're going to convince them that they're wrong, that you'll succeed in getting them to divest themselves of this connection?
Unless you're their psychologist, such a result is highly improbable.
And, while far less charged, the nature of the discussion of someone's videogamey perceptions is also unlikely to go anywhere useful.
IOW, note the objection, recognize it for what it is, and move on to those areas that are truly debatable- how to make combats less grindy, how to convert PCs or other elements from earlier editions, how to design new HR powers/classes/races while maintaining balance, etc.