Possibly, yes.
But too slowly for whom? The berk behind who's totally unaware of the reason you're going slowly and is too thick to look beyond the end of his own bonnet?
Secondly, the tailgater could choose to overtake the slower moving car.
In my experience tailgaters are incredibly bad at overtaking, as they are at all other driving skills. A couple of weeks ago I slowed on the A418 between Thame and Aylesbury because of a retard driving a Clio who was so close I couldn't even see his wiper blades in the mirror. (For clarity I was travelling at nearly 70mph in a 60 zone so hardly too slowly). At this point there was about 2 miles of clear road for this spastic to overtake. Did he? Nope.
The upshot of this is that I continued to slow right to a halt. And he was so bloody close he had to REVERSE to be able to drive around me.
I then followed him (with about 150yards gap) and he duly caught up with the car ahead and preceeded to tailgate that, again ignoring the dozen or so overtaking opportunities.