Ethnic Germans were in many cases, most unfortunately, seduced by Nazi blandishments into the belief that they were superior to their Slavic neighbours. They lived in a democracy - a flawed, but real one - where they were no longer part of the German speaking elite, but part of the mass; and Hitler promised to restore their pre-eminence. Just as Austrians fell for it in 1938, so did the Sudetenland Germans, in large measure. They too voted in favour of the Nazi régime.
http://en.wikipedia.org/wiki/Sudetenland
Well, that's kinda the point. In Austria you didn't see 97% voting for their NSDAP variant. And as your quote says, actual party membership was higher than in
Germany.
Something was awfully wrong there.
And actually Allied observers said so. E.g., here's what Lord Runciman wrote on scene: "
I have great sympathy for the cause of the Sudeten Germans. It is difficult to be governed by a foreign nation, and my impression is that Czechoslovak rule in the Sudetenland displays such a lack of tact and understanding, and so much petty intolerance and discrimination, that dissatisfaction among the German population must inevitably lead to outrage and rebellion."
THAT was also a factor in the British decision. People make it sound like Chamberlain just took a random piece of Czechoslovakia and gave it to Hitler, just to appease him.
The more mundane other factor, though, is that they had waved around the people's right to self-determination when they dismembered their enemies after WW1. And a lot of the pieces taken had essentially been gerrimandered with surrounding territories where people actually didn't really want to go to another nation. (Check out the historical borders of Transilvania vs what was awarded to Romania after WW1 for an EXTREME case of padding it with extra territories and people who didn't want to secede from Hungary in the first place.) In Czechoslovakia's case, 3 million Germans, and areas where they (in some cases) were up to 90% of the population, were forced to be part of Czechoslovakia, although they said from the start -- and all along -- that they don't want to. Where was THOSE people's right to self-determination?
Well, now it turned out that those people are subject to discrimination and intolerance, and keep asking for that right to self-determination too. Could you tell for example the Croats in the '90 to just <bleepin'> stay in Yugoslavia, as they had been assigned? Well, that's the moral dilemma that existed in '38 about the Sudeten Germans. It was increasingly hard to say with a straight face that in the name of the people's right to self determination, those people don't have that right.
And yeah, I'll say it was a flawed democracy. One of the "unacceptable demands" that Hitler told the Sudetenland NSDAP to demand, in order to destabilize the situation was... equal rights with the Czechs.
Mind you, not that I'm saying Hitler was a good guy or actually giving a rat's anus about equal rights for minorities. But, you know, something has to be awfully wrong when he starts to look like the good guy to a minority.