From Natalie Wolchover at Quanta:
The controversial idea that our universe is just a random bubble in an endless, frothing multiverse arises logically from nature’s most innocuous-seeming feature: empty space. Specifically, the seed of the multiverse hypothesis is the inexplicably tiny amount of energy infused in empty space — energy known as the vacuum energy, dark energy or the cosmological constant. Each cubic meter of empty space contains only enough of this energy to light a lightbulb for 11-trillionths of a second. “The bone in our throat,” as the Nobel laureate Steven Weinberg once put it, is that the vacuum ought to be at least a trillion trillion trillion trillion trillion times more energetic, because of all the matter and force fields coursing through it. Somehow the effects of all these fields on the vacuum almost equalize, producing placid stillness. Why is empty space so empty?
While we don’t know the answer to this question — the infamous “cosmological constant problem” — the extreme vacuity of our vacuum appears necessary for our existence. More.
The vacuum problem is just an anomaly, period. Obviously, it isn’t the actual reason the multiverse is hot. The multiverse is hot because alternatives like fine-tuning are not philosophically acceptable, irrespective of evidence. Science will be thrown down the hole before they are considered.
That said, science that amounts only to privileged fluff from people who are designated for social reasons as scientists will seem like an acceptable substitute in the current environment.
See also: In pursuit of the multiverse’s black hole to infinity
and
The multiverse is science’s assisted suicide