I see a lot of people stating their opinions and arbitrarily deciding that people who use 'swear words' are bad at communicating, have weaknesses, or are lazy, but I've yet to see anything objective.
And I think that you've yet to start looking. And I don't mean on Slashdot.
It will surprise you to know that there is a branch of science dealing with questions like: "what makes people better or worse at being listened to and influencing others?". It's called Psychology, and it's about objective study of the human mind. Including personal effectiveness.
Now something tells me that you aren't about to read (much less absorb) anything about Psychology. So I won't bother you with references to the literature (you may use Google if you want to contend that you do).
So I'll try to couch my argument in terms that may be inside your personal sphere of experience. We'll start with advertising. Advertisements are there to make people buy something. They're worth big money because they *work*. Now ... how many swearwords (directed squarely at the viewer) do you see in advertising? And in sales pitches?
That's right: none at all. Reason: they don't work. People would use them if they did ... but they don't.
The same holds for lawyer's briefs, politician's speeches,
If in addition the plain fact that you won't hear any successful managers, professors, lawyers, salespeople, or politicians swear in their official capacity isn't "objective" enough for you, what is?
I would choose the one that's best at the job at hand. At random, if need be. This would be on principle.
You might be getting there. Now lets focus on what you mean by "best at the job", shall we?
There seems to be some romantic notion floating about of the "irksome in manners but super-competent maverick". Most jobs (apart from code monkey or assembly-line worker or data-entry professional) require some measure of interaction. With colleagues. With management. With clients. With prospects. With the public. Being able to do that without needlessly antagonizing people is part of being good at your job.
The vast majority of people I've met professionally (in academe and business) were both extremely good at their work and quite articulate, if not eloquent. I almost never spotted someone with a clear trade-off.
And I also never spotted anyone who was such a prize (professionally speaking) that we had to put up with him/her being a pain to listen to (there was always someone who could do the job just about as well without the theatrics).
So whoever told you that being good at some job correlates with being a potty-mouth? Less fanciful romantic assumptions on your part, and more real-world experience please.