When I say "abuse" I'm counting emotion/psychological abuse, the most common (and as some would have it the most disabling) kind. Our current normative "family" organization is bad because it's a neurosis machine, one, and secondly because it is ideologically substituted for a greater sense of responsibility to community. There's also the still-imbalanced power structure to be concerned about. In most of the world, marriage is still a legalized form of slavery.
I don't expect you to agree with this entirely, but I'm never going to think that the family is the only way, nor that it's the best one. I've thought and read a lot about this and it's not for purely political reasons that I believe it.
What many people don't realize is that the "family" in its current nuclear incarnation (one mother, one father, their biological offspring) is a rather recent invention. For the majority of human history, people lived in bands and tribes where the entire community considered itself responsible for the upbringing of its youth. This wasn't failproof either, but as we've seen with the rise of gangs, cults, political parties, and other loose "collectives", people will substitute for this lack of bigger picture involvement (something our brains and bodies evolved around for thousands of years)--even people who grew up in normal nuclear families--when it doesn't exist in their culture otherwise.
The "family" is probably the most oppressive heteronormative institution there is, and I'm happy to see that it's breaking down all the time.