Destroy magic?

In "The Tavern at the End of the Multiverse" May 12, 2019, Star and friends are taken to the titular tavern by Hekapoo to escape almost certain death at the hands of their enemy.

There, Star decides that magic is the root of all evil, or at least of all the problems she and Mewnie have faced, and she decides to destroy all magic.

What? Does Star want to destroy all Mewnian magic, or maybe destroy all magic in all planets in all universes in all the multiverse, all magic every where and every when?

That seems like extreme overreaction, somewhat like seeing that somewhere on Earth a cobra is about to bite someone, and then exploding the entire planet Earth, killing all life on Earth, including the cobra and the person it was about to bite, in order to save the person about to be bitten.

in Escape From New York (1981) the protagonist Snake Plissken is on a mission to rescue the president of the USA and get him to a peace conference to end World War Three before it becomes a nuclear holocaust with hundreds of millions of people dying. But in the end the "hero" Snake Plissken gives the president a fake vitally important tape, sabotaging the peace process and risking the lives of hundreds of millions of people.

in the sequel There is a device which can stop all electronic devices in the world, thus plunging civilization into to chaos. Snake Plissken activates it at the end of the episode. A world without electronic devices can support a much smaller population of people than a world with electronic devices. Thus Snake Plissken probably kills billions of people by using the device. And if it makes it permanently impossible for electronic devices to function on Earth Plissken will have caused civilization on Earth to be forever backward and primitive and thus cause countless deaths due to backward technology each year for countless tens and hundreds of thousands of years in the future. Snake Plissken makes Hitler seem like a nice guy.

So if countless worlds and dimensions and universes in the multiverse in Star vs the Forces of Evil have magic and use magic as their foundations, those worlds and dimensions and universes - unlike Earth's universe - probably can't function without magic and will be destroyed along with all the countless beings and people in them.

In short, Star's plan to destroy magic to prevent comparatively minor disasters could result in so many deaths that Thanos would seem like a nice guy compared to Star.