It does not cut it's own throat. It works the same way as other standards - it is taking out competition. Access to loans is only late addition, although it by itself is enough motive in fiat economy. Getting access to money printer for negative interest rate is worth a lot of money, sure they can hire a few people to write some ESG bullshit paperwork, it's cheaper than whatever they make on interest only. 

But the real thing is capture of the market. Big corporations enforce this bullshit through network effects. Want to be a supplier to IBM? Sure, show them your ESG project. Want to do consulting for a bank? Oh sorry mate, even though you are single contractor, we can't accept suppliers without ESG. Because we want to keep our ESG certificate too and if we contract with non ESG entities, we lose it. 

Basically ESG is creating special market with privileged access with cheap credit and cheap competitors out. And they get preferred access to money printed by the state (budget)