It's a populist issue because it sounds vaguely correct and being angry at Wall Street is ever popular. That's also why this idea is being floated before the mid terms.

That doesn't make it correct.

Left-populists and right-populists like to frame issues as being a conflict between the elites and the common man. Banning big banks from owning homes is a perfect example of this.

It's fine to ban big banks from buying homes and wont do damage to the nation, but don't expect it to solve the problem.

High housing prices are due to zoning-based supply restrictions. These are entrenched due to politically active NIMBY voters.

Actually fixing the housing crisis means addressing zoning, but that doesn't fit the elite vs common man narrative so gets ignored by the populists.

It's because of emotionally charged response. Leftists largely don't want corporations owning houses, because it's "impure" and capitalist. Rightists largely don't want renters to live in homes that used to be exclusionary on the basis of being able to buy a home. Though there's crossover on the reasons, of course.