However, simply circle-jerking and avoiding debate entirely really is no better for the community image than spitting vitriol. In fact, creating a bubble where everyone shares the same opinion ultimately leads to a poor ability to engage with people who think differently. It also makes the anime community look uninviting to someone who wasn't particularly taken by the show in question; making it seem they would be shunned for having a different opinion.
I think it is important to not only be open to others opinions, but also willing to engage them with a level of civility. To be willing to let your opinion be challenged, and to respond with rational, rather than untempered passion. This is not to say you shouldn't defend your position, you certainly should, but rather you should defend it in a way that propagates further discussion, rather that devolving into a pointless flame war.
This is entirely possible. In fact, I've had more than a few reasonable debates with others on this app. For example, this one with KanadeSong, regarding one of my favorite anime