system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Magneto from the X-Men Franchise would have stopped MCU Thanos easily.

To start, all you need to do to prevent Thanos from using the stones is to keep him from closing his fist. Since the gauntlet is metal, Magneto should not only be able to keep the gauntlet open, but he should also easily be able to yank it off of him. If Iron Man and Spidey managed to nearly tear it off of him, a man who moved the Golden Gate bridge from a mile away should have no issue with taking the gauntlet.

Now, if Thanos already has all six stones, he can pretty much end anyone instantly. He theoretically could destroy Dormammu if he wanted with just a snap. Therefore, Magneto loses here.

But if Thanos doesn’t have all six yet, he stands no chance. Even if Thanos stripped nude to get rid of his armor, he has shown to be able to murder people just by them having too much iron in their blood. He would find a way.

Magneto buttfucks Thanos.
gpt
>Since the gauntlet is metal, Magneto should not only be able to keep the gauntlet open

Only if it is a ferrous metal.  Magneto has power over magnetic fields, which means that he has zero power over objects that are not magnetic (hence the plastic prison).  We have no idea what the gauntlet is made of, but if it is primarily made out of something like aluminum, copper, lead, tin, gold, etc. then Magneto can't do anything.  Magneto is just an old dude that will get his ass kicked.

To your point about the blood, same issue.  Thanos is an alien - we have little evidence that his system uses iron to bind oxygen in his blood or uses it in a quantity that Magneto could take advantage of.  This isn't far-fetched - many animals on earth use hemocyanin rather than hemoglobin to transport oxygen - replacing copper with iron to bind the oxygen.  Copper is non-ferrous and not magnetic.

If he doesn't, then Magneto loses again.