Oh, dear.
So sorry about that, no one's trying to make fun of anyone (at least, I'm not, and as I read it no one else is, either). Clearly some things are definitely being lost in translation.
The expression "beating a dead horse" is used whenever a topic is hashed out, rehashed, and then revisited again, even though either a) everyhthing that could be said has been said, or b) it doesn't matter. In this case, the difference between what DSL said and what others said (was it you? I don't remember anymore) was so minute as to not even matter. Discussing the characters, and discussing how Jeph depicts the characters, is essentially the same thing. Either way, we are discussing Dora, Tai, Marten, and how they behave, because that's what Jeph is depicting.
However, you (and others) seized on a slight difference in semantics, even though DSL disclaimed it (as I recall - I'm not going through the whole thread again!)
So that's why we've been calling it "beating a dead horse". There's really no reason to keep going around about a difference that really doesn't exist!
And again, sorry for making you feel like your English is inadequate - it's really very good, but as I'm sure you know, there will always be some idioms that just don't travel well!