My contention is that flu shot MAY cause immune system problems. Especially for weaker folks.
There’s zero evidence to support that theory. It’s not even a theory really; just a complete guess which I would guess is based on an inaccurate understanding of how the human immune system works.
Meanwhile, Influenza kills tens of thousands of people every year. Rather than scaring people with mystery theories about the flu shot that have zero supporting evidence, we ought to be encouraging everyone who can get inoculated against Influenza to do so. That has concrete evidence to demonstrate it saves many thousands of lives.