For the writers in the "hell no" camp of using certain words, telling a story without them can become complex. A character doing something ridiculous in modern times is rarely told he's being preposterous. A highly erratic protagonist isn't going to be told by each character her demeanor is strange or odd, though it might work for a few characters' interactions.
Child characters are even more difficult. Few children know words like "ludicrous" or "off-putting", and probably wouldn't use them if they did. Unless one avoids putting kids in a situation where they need to address someone (or something) with extreme behavior and/or properties, the writer will need to address it, somehow.
Do writers who see words like "stupid" as ableism give themselves a pass when writing fiction? I haven't asked every single writer, but a fair amount do. Especially when writing realistic, modern stories. It isn't easy to work around words the majority of people use. It's not as simple as avoiding vulgar language.
But a small section of writers refuse to use those words, regardless. Some set stories in strange lands with made-up words. Some don't put characters in a situation where they need to address another's odd mannerisms... at all. Or place their books in a past where different words are said. Or, maybe, they use words like "odd", "strange", "preposterous".
It's up to each writer to decide.
What words do you use?