I never liked Diogenes. I see him as a precursor to Rousseau and the “Noble Savage” stuff that is, in many ways, a bane of civilization.
These guys push it to far. They have this idea and they take it beyond its practical limit.
But most have an idea that is still worthwhile understanding and is useful. IMHO-
Diogenes represents two different philosophical ideals. (1) act like a modern multi-colored-hair with nose, lip, nipple, ear, ... etc. piercings wandering up to random police officers with a megaphone and yelling in their faces while trying to portray this as "honest" and normal behavior; (2) constantly questioning purported truths and pointing out where they fall apart.
The first is just a better-done version of what the skinny black jeans crowd does but with more integrity. However, having more integrity while behaving like a heroin addict hopped up on LSD doesn't add value.
The second is more important. For "settled truths" or "truths from authority" (the latter is mostly the Platonic propositions Diogenes famously railed against ('Behold, Plato's Chicken')) that Diogenes was often addressing it's hard to get people to break out of their comfortable embrace of what they think they know without acting out in such a way that it draws their attention to the flaws or weaknesses in the settled truth.
This is why the Cynics and their more modern nihilistic heirs (e.g., Wittgenstein and Critical Theory) are both important and awful. They're important because they embody the ethic of questioning and critique. They're awful because idiots who don't want responsibility and don't have the intellect or wisdom to do a valid critique nonetheless assume that as long as you're pissing on some perceived established authority then that's a valid critique.