Cobb being a lousy human being is absolutely a mark against him, but ultimately being a dick isn't viewed as an integrel mark against the sport itself (unless you annoy a current baseball writer, then watch out). If you wanted to compare and contrast the making it past the pearly gates odds for Cobb and Rose and wanted to say Cobb losses that matchup, I wouldn't really fault you there.
But again, gambling on baseball has been the universally understood red line that nobody can cross for as long as anyone's been alive. Nothing else potentially dillutes public trust in a sports body like the idea of anything being rigged, which is why anyone getting caught betting on the game while being involved with the game results in MLB clamping down hardcore on them.
Rose bet on the game knowing the penalty if he was caught, and he was caught. Him being a less shitty person than loads of other people doesn't mean that the potential harm he could've caused the game wasn't worse.
Or, at the very least, Rose is the ultimate example of not needlessly denying everything for decades and then only admitting to it for a book deal, compared to Cobb fighting a potential gambling suspension immediately way back in the day and Ohtani being able to pin the blame on someone else immediately (editorial note: not saying necessarily unjustly, but the whole thing still smells fishy to me) versus letting it drag on for decades stubbornly.
That all being said, MLB and other sports being so damn in bed with sportsbooks post-covid is absolutely going to have a massive reckoning eventually.