A brony is a brony, amsterdamman.So what if they make TF2 mods, or have MLP backgrounds, or wear some merch?
If you want to express yourself via that, why not?
Hell, this is my wallet right now:
Made it myself. In fact, I may even fit into your category of those who take it to far.
And as for pony pr0nz, again: so what?
Rule 34 of the internet applies to much MUCH worse than FIM. As long as your fapping habits don't directly or indirectly hurt anyone, everyone is free to yank it to what they please and it shouldn't bother anyone.
Hell, I even the shows' s creator is fine with it.
/everyone with porn emblems deserve a good dropkick xD