Prostitution convictions aren't necessarily felonies.
http://law.onecle.com/texas/penal/43.02.00.html
The first three times are misdemeanors (the very first time it's a class B misdemeanor, by the third time it's definitely a class A), the fourth conviction it becomes a felony.
My suspicion is that misdemeanor convictions may be more of an uncomfortable shame hurdle the individual goes through, having to reveal it, than a real hurdle to being hired by a company that really needs the help, fewer applications than openings.
Now, if the employer has a ton of applications and just a few openings and can afford to cherry pick, they may use the conviction as a convenient excuse. But without a conviction they could still come up with any number of reasons to not hire someone: underqualified, overqualified, too long of a gap in employment (a real problem for a provider to explain if she's been out of the work force for a while. Makes it seem like a lot of other prospective employers may have seen their application and taken a pass or that they're deliberately withholding the names of past employers with whom they had a very bad work relationship who would give a damning reference. That damage is unfortunately self-inflicted thanks to the off-the-books financial allure of the hobby).