Actually, in a weird way, I think it is GOOD that these things are looked into.
A few weeks ago I got a call from the bank. They had cancelled my debit card, because of a weird, small payment to the States (something like 90cents). They were worried that it was someone testing the card out, and didn't want a big fraud to happen. As it happened, that was dh using his card (which has the same number) to buy some sheet music. I verified this with dh, phoned the bank back and they reinstated the card.
In the same way, if someone was posting as me on MN (either me or someone else), and enough detail had been given to identify me, I would hope that MN would follow it up - if it wasn't me I really wouldn't want someone POSTING as me. And if it was then it would be very easy to say 'actually that is me.' Otherwise, using the JudgeFlounce situation as an example - he had taken on a real person's identity, and then using that identity of a QC, posted very dodgy legal advice, and that could come back to haunt the innocent QC - say in a job interview, or if someone on here had a grievance.
Checks can be very useful - they're not always insulting/harrassment.