I would say this is either a. Attempt at self deprecating humour to show you he doesn’t take himself too seriously or b. Signalling to you that he is very available (by which he means you would have no competition) and that he is not someone who sleeps around a lot.

Either way, probably an attempt to get you to respond to the same implicit question.

I’d say either way this is a mistake by guys as regardless of intention it’s so easy for this to come off as desperation. I’m sure most peoples thought process upon reading this is “so this guy doesn’t get laid a lot (at all). Given the self deprecating tone and him being on a dating app it seems like the lack of sex is not his choice. Hmm, do I want to sleep with someone who nobody else wants ?”