Germans bare the responsibility and shame of Nazi Germany, whether they participated in the gassing of jews or whether they sat on the side lines and pretended everything was normal while the country went nuts. We don't excuse the actions of Nazi Germany by saying "Not all of them voted for Hitler, he came to power with a minority government, most were good people! No fault!". Doesn't matter that they were living under a fascist government.
We (western democracies in general) have applauded people who took active measures against the Nazi government -- people who hid / saved the lives of persecuted groups, people who subverted / killed fascist agents, etc. There are stories of escort girls, who killed off Nazi soldiers -- we don't stop and say "Wait! Those soldiers she killed were forced into it by a bad economy, and they just worked back-office jobs, they were innocent!". Instead, we say "Good work, lady". We curate museum installations celebrating in her honor.
Germans who fled Nazi rule in Germany were explicit and generally very vocal in their criticism of the regime. Not apologetic about it. They didn't want anything to do with that stuff -- many effectively severing their roots. So, like, if a Jewish person/group in Canada wants to be thought of as not being part of the genocide, they need to come out very clearly, publicly, opposed to the Israeli Zionist movement -- Avis Lewis (NDP leader) makes that sort of thing known, for example, so he's got some moral backbone at least. Most Canadian Jewish organisations / temples / etc still generally seem 'ok' with genocide. When most of a group/nation supports an extremist agenda, and/or allows it to carry-on through apathy, it's fair for people outside that group to generalize / assume that any 'unknown' member of that group is likely someone that's either supporting or enabling that atrocity.
Same vibe.