Following up on doesn't necessarily mean suing. But that's the part I can somewhat understand, yes. What's more unreasonable is OP's employer in my opinion.
OP's employer would likely want to avoid looking complicit in hacking a direct competitor to their line of business. What they did does not look overly unreasonable from that POV, the problem is OP put them in a pretty bad position. It's not just about being factually right either, appearances can matter too.