It won't affect Polish companies like you anti-polish foreigners wish.
Of course it will. Polish companies need all the help they can get, and taxing them is the exact opposite of helping them. Meanwhile, anyone with an internet shop that's coming close to the tax threshold will simply relocate to the Czech Republic or Slovakia. I know you don't understand business, but no business is going to stay in Poland if the tax system elsewhere is more favourable.
And the sad thing is that business will suffer, employees will suffer and the jobs market will contract.
It's a basic principle that the more you regulate and tax businesses, the worse the economic situation gets.
There's a good comparison in Bosnia actually - the Republika Srpska introduced a 10% flat tax rate and more or less abolished all barriers to business. It's not flourishing, but it's in a lot better shape financially than the Federation of Bosnia-Hercegovina, which has a complete mess of a tax system and endless bureaucratic barriers.
You don't get business at all, do you?
I have a friend that has a fairly successful online business. If he hits the tax threshold, then he'll simply pay people less. It's that simple.