The proposal only limits payments to companies that have received more than DKK 60 million (around EUR 8 million) in aid. So this is not your usual business owner. These are generally larger companies with a well paid management.
As for companies registered in tax havens, the EU has made an official list of tax havens, which will be followed: https://en.wikipedia.org/wiki/European_Union_tax_haven_black...
It's a short list and it doesn't include any countries where a large company doing business in Denmark would be registered except if they try to avoid taxes. Why should tax payers bail out a tax avoiding company?
The proposal was made by a party in the opposition, which is usually seen as most business friendly ("Venstre"). Interest groups representing the businesses in Denmark support the proposal. I think it's a common sense proposal. Paying out dividends to shareholders while receiving government aid basically means having the tax payers bail out the business owners.
I honestly think the proposal should go even further. The government should take a small ownership stake in companies that receive that kind of money.