As an engineer/developer, you may have an issue with one of these libraries, tools, etc and you'll put in a ticket with all of the details your development expertise can coax out; sometimes you'll get responses of thanks for a clear report, sometimes you'll be ignored, and other times they'll disagree or be unwilling, and now you're stuck.
You'll go to management and ask if they'll pay said company/developer to fix it and they might, or they might not.
You either look for an alternative, write something yourself, or you fork it internally, fix the issue and move on; now you and your peers have another piece of code to maintain because nobody on either side of you would budge.
I've never been abusive to an OSS developer, I've certainly been frustrated, and I'm an FLOSS advocate myself.
Some projects I've worked with, and I won't name names, have turned around fixes in literally an hour, are greatful for a good thorough report and want their software to work for you (and I'm talking large internationally used enterprise grade tools), and others will just be rude or dismissive, but you still have to solve that problem, it's your job.
When I have a job to do I'll just move on from projects that make it harder, and I'll advocate harder for the projects that make it easier, if it's small and generally unmaintained, we'll just fork internally, improve 8t all we want and move on, now nobody in the wider community benefits.
There are other projects that are larger, and we pay them decent recurring sums to be able to ask for a fix or feature to be turned around quick, and it'll end up in their open source code, so everyone benefits from that money this company spent.
When you're a small start-up developer you have far fewer options available to you compared to a large company who can or will throw money at people inside and out to get things done.