It also involves people with no understanding whatever of ME's memory
management -

Memory is there to be used (surprisingly enough!) - and MS takes the view
that the most likely program to be loaded is the one that's just been
closed, so leaves the RAM full, relieving the system of the necessity of
reloading it slowly from disk. If, however, something else is loaded, then
the RAM is very quickly released.

In short the behaviour described there is exactly what it was supposed to
be, no more, no less - and a lot faster if you accidentally close a program
you're working in!!