Hi, UX designer here.
First, when you say UI/UX, that's a red flag to me that you don't understand the kind of design you need. There isn't a "UI/UX design community." They're two different specialties, with a handful of subspecialties in each. If you don't understand your problem, and you're asking a stranger for help, I can completely understand that stranger wanting to make sure you're prepared to be taught all the things you don't know so you can understand your actual problem, and that means they have to invest time in you, which means they want to be paid for that.
Second, I don't work for free. That typically means anything resembling facilitation or a deliverable: a wireframe, a color scheme, conducting research. I'll talk all day long, though, if you're exerting all the effort.
Third, I help people out a lot for free, but I also do it within very narrow guidelines. I see it as a professional obligation, to build a positive understanding of design, to grow the ultimate market for my services.
I help out companies, startups and non-profits mostly by doing pro bono design office hours. I'll do them casually, if someone is referred to me. I'll also do them formally twice a year, helping dozens of startups in a single day, through IxDA Austin and Austin Startup Week. Perhaps there are similar events in your area. Try checking with co-working spaces and startup incubators, for example.
I'll also give pretty much anyone an hour of time on the off chance it turns into an interesting bit of contract work. I'll roll the cost of that hour (or whatever) into the contract, if one happens. It rarely does, however, because, there are very few times where the design question you think you have is the design problem you actually have. I've had people walk out of meetings because I'm asking them questions they don't have answers to. They thought they had one "UI/UX" problem, and I helpfully point out all the other problems they have, and they just weren't prepared to hear that.
I'm guessing when you ask for help with your code, you're not expecting someone to develop an entire application for you, for free. There's a very narrow problem you need help with, and, as engineers both, you and the person you ask can speak at the same level and come to a solution in short order.
It's not typically so with design.
You might "just" want to know what the "best" color for a button should be, or get help with color palette for an entire page so it "pops" more.
If I give you a color for your button, you'll walk away happy, sure, and think I'm swell. And then you'll implement it and your conversion rates will drop 30%, because statistically, you probably don't get enough traffic to know for sure for months. Do you know that, or will you panic? Is it the button color's fault? Is it an anomaly? Am I a bad designer? Are all designers frauds and hacks? I made you happy in the moment but have zero control of your opinion of me and of the situation afterwards.
The best thing for you would be for me to sit down with you and go over the entire page, maybe even all of the marketing for your entire product, to understand where this page fits in. Maybe you don't need a different color button, but a different placement. Or different copy. Or different images. Or a different campaign. Or a different product.
I don't know.
And if you're asking me about a button color, there's a better than even chance you don't know, either.
What I do know is, I'm not helping either of us by giving you a color instead of trying to understand your problem. And the only way I can be sure that you're interested in actually solving a problem, is to see if you'll pay for it.
If I'm right, and you don't know what kind of design help you need, I'd be happy to get on Skype or a phone call with you this week and help you figure out the kind of design help you need so you can find the right sort of design community to ask help of.
But, I don't work for free, and I don't know anyone who does.