> As a contractor he should have STFU and done his job. His job is to do the work he's told to do.

or, told another way: dance monkey, dance.

If companies or managers just want to do the infinite monkeys typing shakespeare approach with 0 critical thought, don't hire / contract senior people.

Someone who doesn't push back on giving an estimate for something they have never seen is useless in a senior role. Sure, the kanban stuff might be a little out there, but if a manager is doing a shit job of blocking tasks mid sprint, again it is better they try and suggest something to help their co workers.