helping clients VS listing and marketing

[Marlene May]

An agent wants to list my house, which is now on the mls via flat fee lister. This is the second time she called about it. She told me that she would work to sell my property if I listed with her. That she would call her clients about it. I asked if she wouldn't work as hard for the 3% as she would for 6, since she didn't have to do the work of listing and marketing.
I asked if she wouldn't show my house to her clients even though she didn't have the listing. Her response was that she would show it more frequently if she or her company had the listing.

Are all agents like that? Don't they show properties that any/every agency has if it's on the mls? Are FSBO's blacklisted by agents/brokerages?

TIA
Marlene