Disagree.

I don't filter what I say to my boss.
I don't filter what I say to HIS boss, the CIO.
I don't filter what I say to HIS boss, the CEO.

If something broken, I tell them.

But I don't bitch to other employees.
I don't gossip.
I don't backstab.
But I will openly advocate firing incompetent people
within my own department, and subtly advocate the
same in others. To people who can make the decision.

Nor do I seed dissent. If someone is bitching, I
tell them to document it and send it as an email to their
boss.

I KNOW one of the reasons I am valued to highly is they
can trust me to tell them when something is wrong.

On the other hand, people to bitch to me since I have
no problem working the levels above me to get something
done.