Yeah that's fair, failing to meet deadlines while sadly being the status quo for these things is a valid complaint. Even if it is like one in ten posts out of like +700 pages of posts. Meanwhile I've seen people here complain about every little thing he's done.
Context is important, over 95% of games on this platform are in HTML, or Python, or just RPGM or something like that. (lo/no code for RPGM's cases generally)
So yeah Java Script, a slowly dying out language is considered hard by these contexts, I get it isn't machine code or whatever would actually impress someone these days.