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.
I was was referring to Diogenes claim that the only way to be happy is to remove material desires. The concept of pleasure, comfort or enjoyment being somehow evil or corrupt an that true happiness, enlightenment, or wisdom only achieves when they are avoided is just as wrong a the hedonists claim that those things are the only source of happiness.
Experiencing pleasure is a natural function of being, at least for higher animals. Even livestock seek comfort, safety. Juvenile animals often play together an enjoy each other.
And if Diogenes couldn’t find an honest man by looking in a mirror. If he couldn’t be honest even with himself how could he discern honesty in others?