While I agree Franken's crimes aren't equal to Moore's, (though both are still sexual assault). I.e. a kiss, and groping for a pic (still disgusting, and awful), vs sexually assaulting, and serial predatory actions on teens. I'm also in agreement for a zero tolerance policy, and think Franken should go for several reasons.
1) It sets a precedent for these types of actions. As in a politician can unwantedly grope, and kiss someone, and keep their job. Or setting a tone that unwanted kissing, and groping isn't "that bad".
At my job, if I were to do those same things, I'd be fired on the spot. Plus it says, "These aren't serious enough of actions to warrant a firing", when they definitely are. It's the same type of sexual harassment we're all trained not to tolerate at the work place.
2) Terrible optics for democrats. Any good Franken could do will be easily overshadowed by this. If Moore joins the senate, he may be expelled, or he could drop out of the race. If he does, but Franken stays in, it looks like democrats have a double standard. Especially given if we condemn Trump's access Hollywood tape bragging about the ability to grope women, but give Franken a pass on...groping a woman.
For years to come, every time Franken grills a Trump croney, or speaks out against corruption, this will be brought up. A shadow that will always hover over Franken's actions.
3) Trust. I think people can grow, and become better, but this is a public servant job. We're supposed to trust our politicians to do what's in the best interest of the country. How is anyone supposed to trust Franken when it comes to voting in women's interest when it comes to sexual assault, or women's rights.
Don't get me wrong, you can look at his voting history. For the most part, prior to this, I thought Franken was a good senator. For his ability to stand up, and ask tough questions if nothing else. However, we have pictures of him disrespecting, and violating a woman in her sleep, and thinking it was funny.
At the end of the day, seeing a politician's true nature in a candid moment can erode that trust. A politician tries to get in office based on being real, and caring about the issues. We hear Franken say he's for women's rights, and see him even vote for them. Then we see him groping someone unwillingly, and unknowingly in his off time. Do we take Franken's words that that's not him?