The consequences of making this change are huge and IMHO hard to fully predict - or at least it's hard to have a meaningful debate about what the impact could be. Walmart for example could have a disaster on their hands - a whole swath of jobs no one really wants to do could quickly find themselves lacking staff. And that's just one example
The Walmart example is a great one of why UBI is a good idea, though. Today they only have employees exclusively due to the "work or die" negotiation position of the workers there. With a UBI, Walmart will only have people filling positions when they offer wages that, at market value, justify the work being done.
Which would also coincidentally mean treating your employees better lets you pay them less, which sounds like a desirable natural motivating force in an economy.
I do not think anyone would argue UBI would not cause a dramatic shift in everything, and as a result the only way to really implement it is slowly - IE, you start people on small cash payments per month, and scale it up to (by most examples) the poverty level over the course of years or even a decade. That way, everyone has plenty of time to react to the economic consequences without a panic, in much the same way states are raising the minimum wage to $15 over 5 years.
But rather than talk about it on HN (like this) talk about it on Facebook or when talking to friends and family IRL. That is how you actually spread these ideas.