The High Holidays they are speaking of are Rosh Hashanah and Yom Kippur, dedicated towards personal reflection and repentance. Definitely not towards bashing Israel.
Then again, the Jewish mourners' prayer Kaddish was never meant for mourning Hamas terrorists, the Passover Seder was never meant for undermining the very reason we celebrate Passover to begin with, and the festival days of Passover were never meant for staging public protests.
Incidentally, on Rosh Hashana, the Haftarah portion for the second day* comes from Jeremiah 31, which carries a message of hope for the restoration of Israel, and includes this:
Again you shall plant vineyardsBut...but...but...the occupation!On the hills of Samaria;
Men shall plant and live to enjoy them.
That would almost be awkward - if not for the fact I am sure none of the IfNotNow-ers will be in synagogue paying attention to it. Or in synagogue at all, to be more precise.
Which is a real shame - they really could do with the repentance.
*Yes, we have the second day even here in Israel, Dicky