BCH is much more centralized,
Exactly in what manner do you assert that BCH is more centralized? (Presumably with respect to BTC?)
plus it's at the mercy of any script-kid wanting to spam it for peanuts and fill it with gigabytes/day of spam. Just because it hasn't happened, doesn't mean it can't happen. I would probably do it myself for 24hrs or so, just to make an "academic" point that the "mempool is full" bullshit and "we need an upgrade" can equally apply to a 8mb chain if one goes out and spams it.
You should do that. I'd be interested in the results of that little experiment. Of course, the results would be more informative if the mempool was spammed to persistently full for days on end.
The marketing being pushed by the same crew is about the peer-to-peer e-cash system, with emphasis on the e-cash aspect. Centralization changes the first aspect: As people become unable to participate as peers, you go from peer-to-peer to a client/server model.
Yet it has been demonstrated that typical contemporary consumer-grade PC running the satoshi client can handle about 100 tx/s. With some simple SW improvements (which, for some reason, core has not deigned to perform), such a typical PC can handle about 500 tx/s. The 'unable to participate as peers' conjecture is shown to be a canard.