Banks already do ask for financials and corporate track record. You're required to stake your own credit when your financials are inadequate.As far as I can see, those providers who require personal guarantees usually do so as a standard condition for almost any new business. Effectively, they consider everyone's financials to be inadequate.
You want that to be illegal? It's better than those companies not be able to obtain merchant accounts?
Someone would still offer the merchant account services to businesses who could demonstrate a reasonable business plan, because on balance they would make money from doing so. Most new businesses are not, in fact, going to experience a 30% chargeback rate four months after the original sale.
The banks obviously know that, they just want (as usual) to privatise the profits but externalise the risks/losses. I have no problem with prohibiting that kind of predatory behaviour. It's a potentially significant barrier to starting a new business, and with the global economy in its current state, allowing absurdly risk-averse banks to inhibit new businesses is exactly what we shouldn't be doing.
If the banking industry had a track record of assessing its clients responsibly and lending (or not lending) based on the results of those assessments and reasonable assumptions, I would be happy to cut them some slack. But we all know damn well that they aren't doing that. And if governments are going to pressure them just to lend to small businesses, they should certainly pressure them to provide basic services to businesses that are viable without relying on loans as well.