Does "irregular verb" have some metaphorical connotation I'm not aware of?

Yes. (At least with a plausible guess at what you're aware of.) The point is precisely the observation you make that these are three descriptions of the same behaviour; the implied criticism here is that you (or some hypothetical person who somewhat resembles you) chooses very differently-biased descriptions of the same behaviour depending on whether it's your own or someone else's. (The comparison is of course with irregular verbs in natural languages -- I am / you are / he is. The main point is the difference between the "I" and "he" versions, the "you" typically being something intermediate.)

So it's more or less an accusation of insincerity. Salemicus is suggesting that you are hostile to some varieties of eclecticism when other people do them, but not when you do the same yourself. (I have no idea what evidence, if any, he has.)