Zionism is a political ideology which upholds the decision by western countries to drop an abusive apartheid ethnostate on top of a pre-existing civilization in historic Palestine and then defend it by any amount of violence and tyranny necessary.
The majority of the people you see defending this evil are non-Jewish westerners with no connection to the Jewish faith, so to equate Zionism solely with Judaism (and vice-versa) is just a casus belli to crack down on righteous dissent and, more broadly, free speech.
For instance, in Australia you can be arrested and sentenced to months in prison by simply uttering "Zionism is terrorism" : archive.is
You can be sentenced to prison in an otherwise progressive and democratic state for simply pointing to the overwhelming evidence that zionists have been terrorizing the native Palestinian peoples for almost 100 years.
Positively, er, Trumpian. Coming soon to the red white and blue near you.
America First (After Israel)