Contrary to the top answer, I don't think submit a patch means "we don't care if you like our product or not." It means "we are busy improving the product in many other ways."
Apparently, some people think "I have added your request to the end of our infinite backlog of requests" is a more productive response. "Submit a patch" not only conveys the same info, it also provides concrete advice on how you can jump the queue.
I think saying, "we think it's a good idea because.." or "it's not a good idea because.." or "hmm, that's interesting, we'll need to think about it." are all better responses than any of your quotes.
If somebody cluelessly expresses urgency and wants it fixed now, it's perfectly ok to say "if you need it soon you should consider paying someone for it". But I find "submit a patch" often used when people disagree with your suggestion but can't articulate why.
In at least some of these discussions, I think "submit a patch" stands for more than just the literal phrase, it's a whole category of response, in contrast to the "I will do your bidding, master" category. I will sometimes use the phrase literally, but haven't found the shock and outrage of asking somebody to fix their own problem is diminished much by flowery phrasing.
For the record, I will not say "submit a patch" for a bad idea, I will say "that's a bad idea". Not that people like hearing that, either.
To be fair, I have told people "patches welcome" more times than I can count. And it's because I could not give even the tiniest flying fuck if they use my software or like my software. (And that sentence doesn't even begin to convey how little I care. Patch welcome!)
But on the other side of the coin, I've never turned down anyone's request for a commit bit.
Yup, I always try to indicate in the initial response whether or not such a feature would be considered for inclusion as well. I.e. "Sounds reasonable. I'll try to get to this when I can. Feel free to submit a patch in the meantime." or, "Not sure this would be a good fit because of ____. Feel free to submit a patch and I'll give you a more detailed review."
These terse responses are always open to misinterpretation, especially by non-technical users who may not fully understand open source. That's the problem. "We have a backlog, but you're welcome to contribute to speed things up," or "I do this as a hobby, so take it or leave it," at least expresses some reasoning.
So, a response that would be less likely to offend might be "I'll add that request to our queue, but there's already quite a backlog. If you are so inclined and able, feel free to submit a patch to bypass the wait."
Apparently, some people think "I have added your request to the end of our infinite backlog of requests" is a more productive response. "Submit a patch" not only conveys the same info, it also provides concrete advice on how you can jump the queue.