He just feels it's not his responsibility to enable it, and that the government forcing him to is violating his freedom of choice.
At least, that's one of the things that bothers me about it.
Civilized society is all about trading individual freedom for group stability, and perhaps UBI is on balance a good idea.
I'm not sure myself, but I tend to be skeptical of claims that "X will solve society's woes."
Giving people wealth doesn't change them, and it has really fouled up some places - look at what happened to Haiti after the earthquake when all the aid poured in. Local farms largely died out because they couldn't compete with free food, and as a result the country became less self-sustaining and wealthy.
So, yeah, I guess I have similar concerns for UBI.