Supporting the state of Israel, at a time when it is actively committing a genocide, is supporting the genocide. Genocide should be a red line that forces people to stop supporting its perpetrators, and anyone who doesn't withdraw support once a genocide starts must be, on some level, okay with it.

Existing within a state doesn't automatically imply support for it. Most people have at least something they want their state to stop doing, and that can and does include existing. It's hard to say that a charity issuing statements that Israel is an "apartheid regime", "no longer a democracy" and "committing genocide" supports the state of Israel.

There are also plenty of people who, if asked, would say they support the state of Israel, but wouldn't support genocide, and not see that as contradictory because they're under the impression that Israel isn't committing a genocide. What they're supporting isn't the state of Israel, it's a hypothetical alternative state of Israel that doesn't exist. If (pretending for a moment that the USS Enterprise wasn't decommissioned in 2017 and was currently in the Strait of Hormuz) someone who mistakenly believed the United Federation of Planets was real expressed support after hearing in the news that the USS Enterprise had fired on other ships, it'd be most reasonable to just ignore them rather than assuming their opinion of their imaginary state was relevant to what their opinion of the real United States would be.