No it doesn't.

I'd be very willing to bet that the same qualities that drive someone to use a crude username may cause that person to be less desirable in several aspects of professional life.

It's sad that this has to be spelled out.

Their username suggests that they're related to the porn business (dong == penis). Stripe (and any credit card company) has rules about the types of businesses they will support/allow. Porn "Adult" sites are on the prohibited list. https://stripe.com/ca/prohibited-businesses

Or maybe the user just enjoys penises, or wants more dong for himself at a personal level. Not everyone uses HN as an extension of their business/professional interests.

perhaps - but the parent was questioning that the username did not provide a hint about the reason. I think it's fair to say that's a reasonable hint. It may or may not be the actual reason he was denied of course.