First of all just because a person might suffer
some obsessions related to OCD, does not mean that he suffers from
all of them. If a person feels obsessively compelled to wash again and again it does not naturally conclude that he also suffers from "disturbing sexual or religious thoughts" or "feelings of fear, disgust and doubt". If what you have mentioned above is
all the evidence that Sina has put up regarding OCD, then it becomes easy to prove that Sina is trying to prove Prophet Muhammad being obsessed with remaining clean or washing (which has hardly anything wrong with it) and very maliciously and fallaciously link
that to "disturbing sexual or religious thoughts".
Furthermore, if the entirety of the "proof" of Prophet Muhammad's alleged OCD consists only of "washing three times" then this accusation is pretty much easily refuted. The fact is that, washing three times in ablution is
not obligatory. It is the recommended approach but not compulsory.
"Al-Nawawi (may Allaah have mercy on him) said: The Muslims are unanimously agreed that what is obligatory is to wash each part once, and that washing each part three times is Sunnah."
What is really damning evidence against the OCD allegation is that according to the recorded narrations Prophet Muhammad varied the number of times he washed each part.
"There are saheeh ahaadeeth which mention washing each part once, and each part three times, and washing some parts three times, some two times and some once."
This
variation, depending on the severity of the disorder, is hell for a person suffering from OCD. A lot of times it is extremely disturbing, if not entirely impossible, for an OCD person to vary their routines. This causes
much frustration in the person and in some cases such persons might even feel like losing their sanity. Such variation is very solid evidence supporting the fact that the person does not suffer from OCD, at least not presently.
Reference source:
https://islamqa.info/en/72450