A 'clickthrough' is a page or page overlay you have to click a button to get through, such as Archive of Our Own's TOS page. I was indeed referring to itch.io's standard NSFW warning page, which the game in question did not have, presumably because it was not flagged. I suggest that a calmer demeanor when talking to people who use unfamiliar jargon will lead to more pleasant future conversations for you.
I have uBlock, and it was not completely implausible, before I checked, that a NSFW warning overlay did exist and uBlock was blocking it. (I do use adblockers to shield myself from pornographic content, but only as a supplementary measure.)
The administrator who already replied to me implied that your suggested course of action - which I also suggested as a feature request - was not actually supported by the report function as it is currently implemented.