If he wasn't a hardcore Liberal right down to his DNA, I might consider thinking about possibly weighing the pros and cons of contemplating whether or not I should maybe ponder voting for him.
But since hell has still not frozen over, that's just not going to happen.
I support him running though, 100%.
When the left tells you that he'll erode Trump's support, what they're really saying is they want Trump's supporters to stop him.
In other words, they just want RFK Jr. stopped because they know he'll take waaay more votes away from Biden than he will from Trump. That's painfully obvious to anyone with two brain cells to rub together (which excludes most libs and absolutely excludes the media.)