Re: why do people outside Aikido for IS?
At least in my little part of the world, I don't think anyone thought something was missing from their Aikido. I don't think anyone was looking outside the Aikido world because they were dissatisfied, tho people did train outside of Aikido to broaden their knowledge as martial artists.
Certainly I spent a long time bouncing from dojo to dojo, dissatisfied with what I found. But then I found my current dojo and not only did Sensei knock my socks off, but all his students did too. I settled in there and was happy. Sensei has always been on a search for ways to improve his Aikido and is always mixing it up, but except in that general sense there was no feeling that we were missing something.
Then some guy came to one of my teacher's senior students and said, I met this amazing guy at a Tai Chi seminar, you should come train with him. And that student told my teacher the same thing. And my teacher told the rest of us.
So it was a recognition of something valuable that we wanted once we saw it, rather than a dissatisfaction with our existing practice that motivated pursuing the aiki training.
As for the language people use on the forum--well, this is a discussion forum. People do cross the line, sometimes. But think about it--if someone points out a flaw in your technique, are you insulted, or do you consider whether they're right? Howabout online? Are you going to refuse to listen because you don't like the way it's phrased? Sometimes truth hurts. Sometimes people are just being jerks. Sometimes the jerks are telling truths you need to listen to. What do you care more about, your art or your ego?
You may decide life is too short to deal with jerks, which is fine. But as Jesus said, the jerks will always be with you. Well, maybe not, but I think it was something like that. They're not going away no matter how often their failings are pointed out. So my take is that life is too short to fix the jerks. Take what they have to offer, enjoy their tirades, tolerate their failings. Walk away from the rest.