Being a gentleman of a certain age myself, I get where you're coming from.

Having had a little think about it as a result of reading your post, I wonder if it comes down to sincerity. I think it does for me.

If you're just shilling something that you don't believe in just for the cash then, yeah, probably your hustle is also selling out. Like any verb there can be positive hustles and negative hustles. But would I criticise someone for selling out? I dunno.
Thinking some more, you could argue that the influencer has spent time and effort building up their audience. Why shouldn't they rent some of that space out now and again for advertising to recoup on that investment? 🤷

But if you're promoting something you believe in, or like, or even use - then I have less of a problem if you get some coin for that. As long as it's clear that you are getting paid for promoting what ever it is. That's not an unreasonable hustle, IMO.

I'd be loathe to criticise anyone for their hustles (as long as no one is getting hurt!). Everyone's got to eat, but if you can hustle and maintain a bit of integrity as well, then fair play.

But, like you, I can't say with 100% conviction that I wouldn't turn down a wad of money to promote something if I was approached. Which I'm not likely to, going by at my reach on SM!! 😉😁