You know, aside from there being litttle merit to their claims and all. Israel is about as trustworthy as North Korea when it comes to their systematic ethnic cleansing.
But let's assume they were telling the truth, as genocidal ethnic cleansing monsters are prone to doing.
13 employees of 30,000 were accused of aiding HAMAS. That's 13 / 30000, or 0.0043% of the employees. Do tell me how that's sufficient justification to bar aid for millions.
Hint: It isn't, unless you are using it as a pretext.