Yes, in the meantime some more research has been conducted, some of the people that voted 20 times for the Israeli song without actually viewing the festival have been identified and interviewed in todays paper.
As it turns out they are not necessarily Jews or even Israelis, nor were they influenced by the Israeli state campaign for support since that was targeted specifically at European Jews.
No, there were apparently several thousand Belgians that considered the Eurovision contest as a good opportunity to manifest their support for Israel and specifically for this singer whom they perceive as being unfairly treated amidst what they consider to be pro-Palestinian stance of the public and mainstream media.
A "protest vote" for the underdog, if you will, don't know what to make of it, or what conclusion to draw from it tbh.
Fact is that while the number of viewers halved in comparison to last year, the number of votes was higher (in Belgium), indicating political motives on the part of the voters, they apparently see the contest as an alternative election, one they can influence directly with limited numbers and multiple votes per voter, unlike real elections.