"Can democratic state do without any secret service at all?"

Maybe. But probably they won't stay democratic for long. Some people are only there to make a mess.

"There should be no blank exceptions to free speech"

Remember that this works for the WBC. I'm not saying it's bad, but it's a consequence.

"you should have right to publicly criticize your employer"

But this is like it is. Free speech does not mean speech without consequences, but it means you have the right to speak your mind (as opposed to a "preventive silence")