Ebert never demonized entire groups of people, or made racist or disgusting remarks about them. Even when he made a dumb statement about video games not being art he made his argument respectfully and dealt with the criticism respectfully. His perspective was completely ignorant, not as glaringly stupid and lacking in reason as Sarkeesians, but it was still from the point of view of someone who never played games. However, he didn't run to the media about being a victim. He was the media, one of the few good ones in an industry of trolls and he respectfully disagreed. When he realized he couldn't convince anybody he wrote a follow up article and left it at that. He was told he was wrong many many times by many smart people, and probably a few trolls as well. He handled it like a reasonable adult.
Sarkeesian on the other hand responded by playing the victim, demonizing her critics, and using the media to write a narrative that she was the victim of an "abuse" campaign. The negative response Sarkeesian gets is as a direct response to the way she insults and generalizes entire groups of people, making arguments from ignorance. She's also taken huge amounts of money in donations and failed to deliver on her Kickstarter promise which is now overdue by 3 years. She is considered to be a scammer, but also a racist and sexist scam artist who avoids addressing her critics directly, and instead uses the media to attack them indirectly. Hopefully that should explain why she gets a more negative reaction than Roger Ebert.