The company that wound up buying the building/renting it permanently had SA investors, not Qatari. A breakdown: Step 1, Kushner tries to sell his building to Qatari investors but they refuse. Syep 2, during a diplomatic conflict between Qatar and SA, Trump publicly shuns the Qatari on twitter — which people are reading as revenge for Kushner getting turned down — because Qatar didn’t pay, they don’t get Trump’s support. Step 3, after shunning Qatar, he simultaneously supports SA in the conflict between the two. SA sees that Trump’s support is conditional on getting money for the building. Step 4, the building gets funded by money that ultimately came from SA.

Basically people are connecting the dots that Trump’s support of SA in revenge for Qatar refusing to invest in the building led SA to ensure that political support remained by investing in the building.

Really simplified: Qatar didn’t give money, Trump said mean things about them on Twitter. Then Trump said nice things about SA on Twitter, and suddenly we find out their company gave the Trump family money.