Yes, it is true.
In The Netherlands, literally 9 out of 10 events on the national Jewish calendars are Holocaust remembrance events. The Holocaust remembrance events outrank everything else.
The main and most important thing young secular, unaffiliated Jews know about Judaism is the Holocaust. That is the primary thing about being Jewish – being a 3rd generation survivor.
This is extremely damaging. Instead of focusing on our chagim, on happy things, they spend all their time mourning the past. For all of the remembrance days, large crowds show up: for 27 January (Auschwitz liberation day), for 4 May (Dutch memorial day), Yom HaShoah, and others.
But where are they on Purim? Where are they on Sukkos? Where are they on Pesach?
There is nothing wrong with remembering, but ‘Holocaust memorial day’ should be Tisha bAv, as our gedolim have always said. Some, such as Rav Shimon Schwab and the old Bobover Rebbe, and others, wrote kinnos.
Apart from the issur on making new special days (the English-Israeli Yated Neeman has a couple of articles about this from years ago), there is the issue that we should not create more and more sadness.
I post a link there: http://www.chareidi.org/archives5765/KDS65oyomshoa.htm Mods, I assume this really should be fine.