I believe the fact that F2P players can only get rewards from 3 FPs per week might have contributed to this. Since they can only play 3 times a week and get rewards, each time they go into the FP they simply need on everything to "maximize" their loot count.
As a subscriber on the 6 month recurring plan, I have unlimited access to FPs myself so if I see someone doing this, I either go "eff this" and join in the fun or leave and do another FP. No biggie really. Actually at higher levels I don't even bothered anymore because those useless loots simply takes up space in my bag.
^Truth. I have been playing since launch and the random loot claiming has increased a little since F2P came out but it's really not THAT significant. I think people just need to be educated about the rules. It's not gonna stop the looters but honestly, random FP loot isn't worth griping too much over.