No you don't. The beliefs are political. Therefore, it's terrorism. At no point does rationality ever enters into politics; in fact, I find it hard to believe politics have any sort of rational basis at all.
There are plenty of times when rationality figures into politics. I get your sentiment, but people have political beliefs anchored in reality and rationality as much as people fly off the hinges with their political view point. If you didn't put any stock in rationality you wouldn't be voting with as much attention as you're putting in trying to debunk my view point.
Also, I thought the VA Tech shooter publicized a screed against rich people, though I'm too lazy to dig up that screed up. I know that at the time, I thought that screed could be evidence of it being a terrorist attack.
Not trying to be snide, but you wonder why I sort of hesitate to jump to the label terrorist, it's because of stuff like that. Then again, it wasn't my country and in comparison to Breivek, the VA tech shooting was sloppy and chaotic.
We've seen so much violence in the US (Loughner, McVeigh, Kazinzcky, the Ft. Hood Shooting, 9/11 dozens of mall, school and workplace shootings...) I guess I'm just to the point where the only 'terrorists' I feel I can really worry about are the organized terrorists. Because they're semi-organized so they can maybe be caught. All these others guys? They fly under the radar until they pull their thing. To label every crack pot and psychopath with an agenda makes it seem like the 5th Column is right around the corner.