I guess the thinking goes like this: Why start a business, get a higher paying job etc if you're getting ~2k€/mo in UBI and can live off of that? Since more people will decide against starting a business or increasing their income, productive activity decreases.

I see more people starting businesses because they now have less risk, more people not changing jobs just to get a pay hike. The sort of financial aid UBI would bring might even make people more productive on the whole, since people who are earning have spare income for quality of life, and people with financial risk are able to work without being worried half the day about paying rent and bills.

It's a bit of a dunk on people who see their position as employer/supervisor as a source of power because they can impose financial risk as punishment on people, which happens more often than any of us care to think, but isn't that a win? Or are we conceding that modern society is driven more by stick than carrot and we want it that way?

If everyone has 2k/mo then nobody has 2k/mo.