We aren't talking about a country in the Global South, which is bombed and then chastised for not having gay rights. We are talking about the communist party of an EU member state. The much simpler explanation here is that whoever wrote and then greenlit that communiqué has brainworms.
Here in Brazil we even have meme parties that are more reactionary than Hitler, but are called something along the lines of Communist Part of the Working Poor or whatever.
Just tell them that Israel's offers of Palestinian statehood were no different than the current occupation of the west bank. Then blast the waves with witnesses of israeli soldiers being trained by arresting innocent palestinians, or the record growth of settlements. Ask them if if full statehood is possible without the right to defend oneself, given that Palestine wasn't allowed to have an army or manage their own water resources.