I'm not far from being an older dev, and I've been struggling more and more with cynicism in myself. Everything you said is 100% true, but I have to force myself to avoid phrases like "technology fad" or "young, excitable devs" when I'm mentoring younger devs. Because even though those things are true, verbalizing them would demoralize the team.
I don't argue against the latest fads. I hate the idea of Node/Electron/ various JS based cross platform mobile frameworks with a passion, but I do look to see what is paying the most and has the most openings. I'll jump on whatever fad that the market wants.
Older devs, after seeing enough technology fads, are much more sensitive to bullshit. Which makes them a bit sarcastic WRT any new fad. Not a desirable trait from the employer's perspective :)
Sarcasm in general is not a desirable trait. You can explain the pros and cons of different technology choices without being sarcastic.
A green developer who wants to rewrite everything is $LANGUAGE is just as bad as the self-important greybeard rolling his eyes and scoffing at anything that isn't $OTHER_LANGUAGE.
Older developers have seen enough technology fads come and go that they are much less likely to do this than a young, excitable one.