> The existing statements seem like slander no?

I haven't read them, but if they're accurate then they're not slanderous.

I know that if I was slandered I'd be quietly fuming and instructing lawyers, not posturing on twitter and taking pictures of myself 'back in the office' but then again I'm not a tech sector CEO and they seem to be made of different stuff.

What do they say? If the facts support you, pound the facts. If the law supports you, pound the law. If neither support you, pound the table.