To be fair, chilipepper, I think you also misunderstand the OP, though - she talks about hoarding as "despicable" but I think her posts also make it clear it is the "market" ie the system that she is attacking, rather than the individuals.
I would also absolutely disagree with you that BTL is a natural and "normal" part of the market - the situation we have now is not inevitable, nor is it nor has it been a problem in all housing markets in all countries/times.
It is a problem now because of very specific political decisions that have been taken to artificially prop up house prices and reduce tenants' rights, eg Help to Buy, low interest rates, QE, introduction of shorthold tenancies, introduction of easy-to-get BTL mortgages, rules concerning deposits and proof of income required for would-be homeowners but not BTL landlords, ending of MIRAS, etc etc etc.
None of these things are inevitable and on the contrary, represent the opposite of a "free market". Political intervention has caused the housing crisis - it can also end it, if it so chooses. That it doesn't choose to, largely due to a glaring conflict of interest among many MPs, is the problem.