I think of the biggest problems with anonymous apps is the lack of reputation / consequences. I have always believed that anyone can be an absolute troll or a bully or whatever when presented with the right circumstances. Those circumstances tend to apply to far more people when you advertise yourself as an anonymous app.
There was a link to an article posted on /r/philosophy today entitled "Social Networking and Ethics" that has a section about Anonymity versus Commitment. It shares similar sentiments to the ones your express here.
Dreyfus suggests that what online engagements intrinsically lack is exposure to risk, and without risk, Dreyfus tells us, there can be no true meaning or commitment found in the electronic domain. Instead, we are drawn to online social environments precisely because they allow us to play with notions of identity, commitment and meaning, without risking the irrevocable consequences that ground real identities and relationships. As Dreyfus puts it:
…the Net frees people to develop new and exciting selves. The person living in the aesthetic sphere of existence would surely agree, but according to Kierkegaard, “As a result of knowing and being everything possible, one is in contradiction with oneself” (Present Age, 68). When he is speaking from the point of view of the next higher sphere of existence, Kierkegaard tells us that the self requires not “variableness and brilliancy,” but “firmness, balance, and steadiness” (Dreyfus 2004, 75)
While Dreyfus acknowledges that unconditional commitment and acceptance of risk are not excluded in principle by online sociality, he insists that “anyone using the Net who was led to risk his or her real identity in the real world would have to act against the grain of what attracted him or her to the Net in the first place” (2004, 78).