IMHO I would recommend that you write about what’s in your heart. Knowing that it’s controversial can work in your favor if you write about something well enough. You would need a deft touch with any controversial subject. Great writing is great writing, though. It both shines and it can conquer hearts and minds.
Also, colleges are different. Are you writing to a conservative school where the students are more likely to “go with the flow” as established and dictated by authority–just because it is the authority? (maybe Liberty or Wheaton in IL or Furman or Hampden Sydney or the service academies–just guessing here). Schools that hold authority in high regard may not be interested in a person who challenges authority.
Or are you applying to a school where they teach students to “speak truth to power” and to question any and all authority, requesting the people holding themselves up as authorities to demonstrate their validity and positions? (Maybe Oberlin, Smith, Mills, Hampshire, Berkeley, Vassar–again just guessing). They might love a student who admires a potential student who admires a person who challenged existing norms.
Or perhaps you’re interested in a school that genuinely will welcome an intellectual discussion on any subject, regardless of its popularity or political bent, such as St. John’s in MD and maybe U of Chicago. There are many others. They might find such daring honesty refreshing in an applicant.
Remember: while it’s risky to step outside the “bakesale” norm, it’s also risky to stay in it. To be conventional is to be boring, by definition. They may not remember you. “Well-behaved women rarely make history” they say . . . .and I’m sure that goes for many men too.
This discussion on CC might help you, as you can see what thoughts are in people’s heads when they hear the name of a firebrand By bringing those POVs into view as part of your essay, you could help diffuse potential hurt, angry, frustrated feelings that your hero has also caused, beside his positive contributions.
Some call him X. Some call him Y. I call him hero. (sort of thing) and you can acknowledge the difficult parts of your hero without throwing him out the window.
You may also consider saying that writing about a controversial figure is not the safe thing to do for a college app and that demonstrates [fill in the blank] whatever it may demonstrate for you: courage, foolhardiness (self-deprecating humor), refreshing honesty . . . or . . .that heroes are complicated?