What Do We Owe Bands?

Do we owe our favorite rock bands anything? I mean, we buy their albums, T-shirts and concert tickets - isn't that enough?
The other day Nikki Sixx (of Motley Crue in case you stumbled upon this blog by accident) tweeted that he didn't like the crowd at a New York date of their current tour. From what I can tell, no one from Poison tweeted anything negative about the crowd. Nikki's tweet (since deleted) was basically that the crowd was lame. I assume he meant not rowdy. I'll agree it sucks to be in a crowd of people all just sitting or even staring off into space. Here lately, my biggest pet peeve is people watching an entire show... through their cell phone. So I do understand where Nikki is coming from in that regard. But is it okay for rockers to complain about paying fans from the stage... or via social media?
Nikki isn't the first rocker to rant about crowds and he won't be the last. It's hard when a band plays to a super small crowd (now I'm thinking back to Nelson at Rocklahoma a few years ago) or to crowds that get so insane it is dangerous (like when I saw Avenged Sevenfold in Columbus once and the crowd of mostly kids surged, busted the barrier and nearly took down the media area and almost ended the show), but still, performing as promised is just part of the deal. The prices of concert tickets is out of control (we've already had that discussion) so I feel like bands should be at least a little grateful for their fans that are still willing to pay to come out and see a show. And that goes for bands playing at every venue level, from the corner bar to Madison Square Garden.
I dunno. I just don't think it is very nice for any musician from any genre to complain about fans. That doesn't mean artists need to blow smoke or say "Our fans are the best!" or "This crowd is the craziest!" if it isn't true. What's that saying? If you don't have anything nice to say, don't say anything at all?
Flame away.