A lot of companies have a policy of not hiring people that are significantly overqualified for a position. The reason for this is that those people are almost guaranteed to be unhappy and perform poorly. That means that if your company just needs some code monkeys to crank out code to spec then you need to hire people that are perfectly happy doing that because it matches their skill level and ambitions.
Someone with enough initiative to start their own company is not likely to do well in that kind of an environment, and the fact that they look at it solely as crap they need to tolerate in exchange for a paycheck doesn't help.
Fair enough - but then tell the candidate that: "Sorry, you're overqualified, you can find a better position, and be happier. We just need a code monkey for now". None of the BS about "free spirits" and "normal jobs" - I mean, come on.
To flush out this point, consider that hiring someone is not free. There can be significant costs of hiring someone who performs poorly (opportunity cost, training overhead, lost work).
Grammar is about sentence structure; your point is about word choice, otherwise known as "diction."
And "flush" is perfectly correct. Used transitively, it means "to expose or chase from a place of concealment." Example: "the hunters used dogs to flush their game from the bushes."
In figurative language, "flush" is a good choice when you're talking about stripping away extraneous information. "Flesh" is used when you're proposing to add more information, as in putting flesh onto bones.
I should add that I'm only addressing your claim that "flush" is inherently scatalogical, not whether the original use was valid.
After your business has gone so far into the red that you've decided to fold it and just get a job, you, too, might just want a paycheck. It's not necessarily a permanent condition, but surely no company hires thinking that the employee is going to be hanging around their company longer than 2-3 years anyway?
When I was interviewed for the last job I held, I was asked if I will leave the company and be self employee again. Thing is if I take up a job, I find it hard to sustain interest for more than 2 years.
In fact, it seems like the company in question only wants to hire people that "just want a paycheck".