Still doesn't answer the question. Is it illegal? NO.You’re looking at it as if it’s property elsewhere.
It matters because East Jerusalem is occupied territory where Palestinians have restrictions on building permits for their properties. The Israelis with settlers groups have used tactics as house demolitions and withdrawal of residency permits, to change the demographic makeup of East Jerusalem.
Homeowners in East Jerusalem generally refuse under any circumstances to sell properties to Israeli settlers. The vast majority of the properties sold to Israeli institutions have been made by fraudulent or deceptive means, sometimes using intermediaries or straw men to fool Palestinians into thinking that their homes will still be in safe hands. Emirati and Palestinian business men doing this is one way.
You can have your ethical concerns but it's not illegal....Sellers can choose not to sell to the companies that are fronting for the Israelis.