[LunaSea]

I don't understand why this attitude is a problem in this context.

It's their last and only pressure point in the political game that happens in the company.

If you don't feel that your skills are fairly compensated and you can't leave (due to contracting or vesting time) you don't have any other options.

[marktangotango]

Being a dick is not an option or a negotiation tactic, it is just that being a dick. Note I'm speaking to my experience, where tbe people in question do everything but actively sabotage the CTO in question.

[paulhauggis]

"Being a dick is not an option or a negotiation tactic"

I disagree. Leaving is not "being a dick", it's looking out for yourself. If you don't, nobody else will. It's apparent this is the case with the OP: He was pretty much built the entire company up and was there for the company when they needed him (I would imagine late hours, weekends, etc).

Now that they don't need him anymore, they pushed him off to the side. I've heard this story 1000 times and experienced it first-hand.

I don't work for startups for exactly this reason. If I'm spending my life building your company, I better be getting 50% in equity. It's really not worth the fooseball table in the lunch room and the Red Bull in the fridge. This is why you need to get the young and naive to fill these roles.

[marktangotango]

I agree, leaving is not being a dick. Staying and not helping, or actively hindering new staff through lies and misdirection about implementation details of a complex application in a complicated domain is.