Not the person you're replying to, but I'd imagine it means they were raised Catholic, have since left the religion, and don't have a particularly fond view of it (hence "recovering").

To go along with u/Uh_I_Say - having been in Catholic school for 12 years, it's a process to unfuck your head. Especially if you, like me, were bisexual and wrestled with that throughout high school and college until finally having it hit you at 25 that the reason you got flustered when a certain boy flirted with you is because you really kinda wanted him to kiss you. Bonus points if your coming of age was, again like me, during the Afghanistan and Iraq Wars. Cuz then, you got to watch all the people you knew and loved go on about how Islam was a violent religion (sarcastic "religion of peace" jokes abound) and that Christianity was a religion with a "loving god", and then turn right around and banshee scree about how we really just needed to carpet bomb the Middle East, that poor people should suffer more because it'd motivate them, etc.

It's a very ... difficult experience, coming out of all that. For me, it happened because I very much bought into the idea that Jesus taught us to love and be kind to one another, but instead I got a front row seat to people around me waving a book around to justify hate and war, all while demanding complete adherence to that notion lest you be branded "unpatriotic", "unAmerican", or a "sympathizer".

To clarify and expanding on other responses you got, same as a recovering alcoholic or drug addict, with the difference that I did not choose to be a catholic, it was just the culture I was born ( Spain ) there are wounds that are inflicted as a child, indoctrination, with feelings of guilt and shame for things that are out of one control.

Like your gender, sexual orientation, gender identity, race.

The wounds eventually heal but the scars, I will carry to my grave as a reminder that when some people say " think of the children " or " is a slippery slope " they don't mean what you think and they don't have your best interest in mind, just follow the money and you will see what I mean.

We as a society have to make the most urgent effort to get ANY flavor of organized religion as far away from children and schools as possible, and I am not only referring to any of the offshoots of the abrahamic death cult, whether is christianity, muslim or jewish. They pray on ignorance ( hence their insistence of controlling the Education system ) banning books or worse burning them and the people who wrote them as well.

So yes recovering catholic is a very appropriate description for many of us that survived.