Who says they don't have programmers? I would wager that almost every YC company has at least 1 and generally more than one programmer on the founding team.
I also think you're being far too presumptuous about the comp packages these startups are offering. You seem to imply that they're being too stingy. Do you have any evidence for this?
"Not one company is willing to put forth a salary number, but they all say they offer excellent compensation."
The implication being that the salaries offered are low. If they were confident that what they were offering was competitive then maybe they wouldn't be afraid to be up front about it? I've never had to hire someone so I don't know what the reasons are for not stating a salary range are.
You aren't going to get uniform applicants. Different applicants will command different salaries. There's not a reasonable way to put a single number on it. It's not just YC companies that do this, it's basically everyone. Go try to find a salary number on google.com/jobs. You won't find one, and yet Google is known to pay quite well.
When was the last time you saw a salary number for any programming job?
For that matter seeing a salary number in a job add for any high skill professional job is extremely rare.
I also think you're being far too presumptuous about the comp packages these startups are offering. You seem to imply that they're being too stingy. Do you have any evidence for this?