No, stirring the bed removes craploads of detritus, Mainly harmless into the water column which is then thrown down the overflow.
It also removes oxic areas allowing them to build up again.
(Air bubble release whilst stirring).
This process also feeds the corals as small microplankton is in this "dirty water column" for a short time and has obviously got lots of little greebly's now floating around.
Feeding time once every 6 odd weeks.
(In fact I can see my Chromis eating the stuff when I do it).
Too much stirring can cause the opposite, in fact RTN if done too often.
(Not sure why), probably continual dirty water flowing over them all the time.
I run a sponge filter prior to stirring to remove the big particles prior to skimming the rest.