I would actually ask why is Israel allowed to behave in a way other countries aren't. Russia has been widely sanctioned and condemned. Israel has the unconditional support of the USA and has been told there are no red lines (Biden) and been given a carte Blanche by Trump.
Israel have still been allowed to take part in all international competitions.
The EU have have issues no sanctions despite a report saying they have breached human rights.
Defending yourself and killing at least 60,000 people and starving 2 million is not the same thing