DotA/HoN have terrible communities, I'll admit that, but it's because if one bad person is on your team you've already lost, it's calculated and they're trying to troll you out to keep you from playing. Everyone goes through that hazing. If any other online game had that quality it'd be the same way. I'm not trying to vindicate the behavior, just explain it. LoL players see the same thing. Bad people get trolled all the time, and the game is so much more casual.
I'm actually growing more fond of DotA/HoN over League (excluding the community) because it has a much higher skill ceiling. Everything is harder and more offensive based. It's easier to gank/get ganked because towers don't do as much damage. Map awareness is harder because the LoS to screen size ratio is smaller. Laning is more intense because of denies (if you zone someone out and deny you can easily outlevel them) and last hitting is harder. There are also smaller health pools which make fights more intense. Item Builds are more interesting because you're not just stacking stats, there's very interesting abilities. Also, no GODDAMN FLASH. I think a lot of the elements make it harder to access and a lot less casual, but it's a highly competitive game. You just have to take the trolling for what it is and use /ignore.
Another point of contention is the poor balance and metagame in League compared to DotA. In League, every hero has a really strict role. There's actually very few differences in the heroes compared to DotA. Take Ryze, Annie, and Brand for instance. Ryze has 2 nukes and a snare, with an ult that does AOE. Annie has 2 AOE nukes, a single target nuke, a shield, and the ability to stun (and Tibbers). Brand has 2 AOES, one bouncy ult thing, and a skillshotted stun. Look at the similarites between Xin/Jarvan/other tanky DPS. They are very similar. They have their own flavor to keep them interesting but once the metagame reaches an equilibrium there's going to be clear imbalances because they're so perscriptive and one is going to be a clear choice (TF bans anyone?). There's a HoN character (she might be in DotA) that revolves around the use of trees. It can latch onto trees then either pull herself too them doing damage to enemies in the way, or pull the tree towards her. Or take Earthhoof or whatever his name is from DotA that has the ability to make a fissure in the ground that stops movement and makes a stun. There's so much more of a dynamic in individual heroes that makes for a more interesting metagame.
Personally I can't wait for DotA 2, and I know a lot of friends that are the same way. I've played a decent amount of LoL and I like it, but there's definitely a crowd DotA appeals to.
Also, amazing OP. I loled. It really sums up my opinions on Valve after the freemium TF2/cash shop in portal 2. I can't wait to collect hats in Dota2 (no).