I'd say the OP's language highlights an issue that the FGC runs into constantly: Inherent hostility towards new players
Fighting games in general have a lot of challenges attracting new customers because of how unique they are. Not only do players have to learn concepts that don't really apply in any other genre (hitboxes, active / windup / recovery frames, BLOCKING, hitstun, recovery, combo system rules, character nuances, etc.), they have to learn a completely new way to control inputs, especially when it comes to special moves - no other genre requires SRK motions, fireballs, 360's, crescents, etc. Nor do many games use 6 buttons in the way that fighting games do. All of these are barriers to entry.
On top of that, most people need a fightstick to play better (not everyone does), which is an expensive investment.
And the online community in fighters can be... unwelcoming... at times for new players.
Any of these things can cause new / potential players to bounce hard off the game, and we've not even gotten to the why and when of how any of the thigs they learn should / could be put into use practically. Refer to most of Capcom's tutorials as the best example of "rote memorization of something, but have no idea why it's useful or when".
An ideal, well-designed fighting game should help players find the fun of fighting games via great tutorials (most don't do this), a campaign that teaches the game and eases players into fighting game concepts (none have really done this), input simplification for basic actions (some have, much to the angst of others), provides active learning / education when players fail (co-op training option is the only manifestation of this I can even think of), and online filtering / new user corralling (some try this).
If things like autocombos / mashables (aka a "dumbing down") allow new players to find some fun in the complicated world of fighting games, why is that a problem? Unless the high-end skill ceiling is somehow capped (I have never seen this in any fighter that has mashable stuff, btw) this doesn't impact anyone except those in the "kiddy pool" to use a term that goes well with OP's language.
If people are complaining that a game is "dumbed down" it's likely because they weren't going to play it anyway, they're in another fighter's camp (FGC can be very clannish) and want to discredit it, or they weren't that good to begin with and feel their "skillz" are now threatened.
TL;DR: As long as time spent with the game and dedicated "labbing" / practice reward mastery and displays of great skill (mentally or physically) for those that want to earn that, then there's no "dumbing down" claim that holds legitimate criticism.
