There's sth I don't understand when it comes to the concept of "uncertainty" If someone, for example, gets an intrusive thoughts about being attracted to a family member or a pet or a child or anything similar, are they supposed to just say "okay maybe I am, I should accept that possibility" and then move on...?

I usually try to respond to those intrusive thoughts with the grandiose conspiracy theory that would have to be going on for this to take place. For example, I run a DND game for middle schoolers as a part of my job, and sometimes I let them stay on after class for a few minutes and we all hang out and talk. Sometimes OCD says this means I am predator, because I enjoy talking to my students. So I say to OCD: Yes, this has all been a long con for you to groom your students. You are truly evil and despicable human being. No other teachers have fun talking to their students, and the fact that you do crosses a boundary. The fact that you have never experienced attraction to these kids is an illusion and a lie you tell yourself so you can continue to groom them in a guilt free way. And then OCD is just kind of like... Yeah okay fine I sound really ridiculous right now.

I think it’s more along the lines of “Okay this is a thought I’m having. It doesn’t necessarily mean anything about me, thoughts come and go in everyone’s minds. On the off chance that this one is true, how does that make me feel? Am I able to cope with this discomfort? I’m going to sit with this feeling without performing compulsions, and eventually it’ll go away. Next time the thought comes back, I can brush it off with a little less pain/discomfort.” I guess it’s not about accepting the possibility that the thought presents so much as accepting that these thoughts will always come (because they come to everyone, not just people with OCD). And acknowledging that performing compulsions around a thought doesn’t affect the probability of it “coming true” - so your job is to sit with the feeling it causes, with the knowledge that you can cope with it without compulsions. I don’t think it’s “maybe I am” so much as “no matter how minute the possibility, all things are possible”. I guess it’s about embracing Uncertainty The Concept (as the only universal constant) rather than trying to accept any/all possibilities. Just my two cents!!