In reverse order
>It seems absurd
Regardless of appearances, it works. Something about giving shills the opportunity to feel disgust at the amount of detail and effort goes into making top-rate horsepron is exceedingly repulsive to them and normalfags alike. It was never intended at the inception on 4chan, and originally it was a way for /mlp/ to repulse /pol/, but it had the opposite effect. Nazis who had previously felt a similar disgust at the sight of horsepussy observed two things. First, one cant deny the autism on display, unabashed and unrestricted. For two, it gets rid of shills and reddit damn quick. So, absurd or not, if it ain't broke, why fix it? And in the intervening years, horsepussy has become something of a covenant amongst those for whom this is home.
>spamming horsepussy is spam
An understandable position, but one you'll find little support for. Where do you think you are? This board came to be not because threads and topics were banned on 4chan, but the entire board culture which was never asked for (indeed, it was originally a prank on /mlp/ and /pol/) but through the magic of friendship grew into something so beautiful that anons REFUSED to let go of, or give up on. And this is the same board that is giving the space to do whatever it is THIS TIME that 4chan is cracking down on.
A brief perusal of the rules listed in the policy page will indicate that ponies are allowed, no exceptions. This especially includes horsepron. One will note that there is no rule expressly permitting politics, though that's baked into the cake as well.
Tl;dr Horsepussy is here to stay, and objecting to it will only invite more; best to just get over it
Any further questions can be levelled ITT, to avoid any further derailment of other threads, in spite of this topic being at the core of the site, as has been expressly indicated by mods and admins.