"Why should he be regarded as some great statesman when there's ample evidence for how terribly he's treated women."
1. On an objective level, I'd say because statesmanship is not impacted by your own personal life as long as B doesn't cross over into A...for example, JFK, again, was a pretty big womanizer, but we tend to remember him as a Top 10 president both for what he stood for and what he did/was on the brink of doing before his death and LBJ finished them job (ie, the Civil Rights Act.) So what if he was a womanizer on the side? That was a huge character flaw, yes, but if it doesn't impact his STATESMANSHIP, then he should still be hailed as a great president. By contrast--and to pick on a Democrat, in the interest of fairness--Woodrow Wilson's racism got the better of him and led to some decisions while in office that were to the detriment of blacks...and the obvious ones here are those leaders who took bigotry/racism and turned that into genocide. Clinton had his flaws, but as long as they didn't lead to him creating a Fuck Interns Across America Day, he still deserves to be remembered for the merits of his statesmanship...with the womanizing left to biographers.
2. He treated a few women terribly...NOT that many, in the grand scheme of things--again, it's not like his dalliance and not keeping it in his pants with Lewinsky hurt millions of American women the way that (in the minds of some, at least) calling something "legitimate rape" and arguing for (or in Akin's case, against) legislation on those grounds did.