The title of this page should be changed to "Lee Sedol." This is the way he seems to prefer to have his name spelled and is how it's spelled on the Korean Baduk Association's official website. It is common courtesy to spell people's names according to how they themselves want it to be spelled.
I agree that it should be Lee Sedol.
Refer also to the 2016 discussion at Coffee Machine / Old Coffee 2012-2016.
Apart from Lee Sedol, Lee Changho and Cho Hunhyun, the most famous Korean professionals are Shin Jinseo, Shin Minjun and Park Junghwan.
None of those three are named in McCune-Reischaur in their article titles.
This was not a point that could've been raised in 2015, when the discussion last emerged.