Strangely, I am not feeling that uncomfortable.
Cartels are something that in the free world should be able to form. Personally I am not that afraid of troll attacks since I do not simply care, however I see your point, some people might be more sensitive to internet trolls in a way that those trolls might have some power over them. Generally speaking, smart money people however do not care so much about trolls screaming from their caves.
To lend XMR to shorters is basically the only thing one can do with XMR in real world. Personally I am interested in investing to assets that bring me passive income but are also backed by a collateral. XMR loans in Polo is such asset.
This depends on how good the collateral is. XMR loans backed by DASH or even ETH can be very scary. A sharp spike in XMR/XBT could easily provoke a a sharp drop in DASH/XBT creating a double loss for the short XMR position. This has happened before in the spring of last year where a sharp drop in DASH/XBT over the Darkcoin/Dash re-branding caused a sharp rise in XMR/XBT.
Edit: Cartels are a terrible idea, not only can they be illegal in most jurisdictions, they undermine the very essence of a free market; namely competition.