Does the word ‘moderator’ exist in English? Well yes, it does, but not in the exact same way that it is used in Czech. A moderator is someone who moderates, which means he controls, regulates or manages a situation, for example, during a conference call. The man or woman at the centre of things, regulating when people talk etc, is a moderator. We use the same word for the person who is in charge of an examination. He is an exam moderator.
The person who appears on television is not a moderator, or a speaker. A speaker is someone who speaks at, say, a conference. The person who is the host of a TV programme is called a presenter. He or she presents the program, and that could be news, sport or entertainment.
So we say TV presenter, radio presenter, news presenter etc. The only real exception to this is the weather presenter, who we often call the weather man or weather girl.
So, a combining sentence would be:
I think most TV presenters are over-paid and stupid. But then again, what do I know? I am just a humble exam moderator!