I've a always had a real problem with borrow to let. I've a problem with buying properties to rent outright too in a time when housing is so badly mis-allocated, but I think if it's your own funds, then you make your choice.
But borrowing money to do it is much worse because (in my opinion)
#1 It's a leveraged investment which is regarded as a highly risky and sophisticated strategy only to be used by people who fully understand the risks (i.e. not an unshakeable belief in 'property always goes up'). Most people wouldn't dream of doing with other asset types.
#2 It's just totally questionable in a world of near infinite investment vehicles to pick one so intrinsically tied to people's lives, and to do it by borrowing money and bidding against potential owner occupiers doesn't seem right.
#3 (this one might have been a bit too much - see below) the money is credit money created by a bank - i.e. conjured out of thin air on a promise it will be returned by the fruits of some poor person who may never be able to own their own.
#4 I don't even think it's a good investment financially - most people are relying on capital appreciation, the yields where we would be are very low and the rents are dictated by salaries/housing benefit (aka landlord benefit!).
So a friend of mine is (planning on) doing the former. We'd gone out for a chat and we were discussing pensions. She says her and her DH are going to release some equity and look at putting it down on an investment property. I explained the above, and said that she could look at a self invested pension instead - which wouldn't necessarily have such ethical points but she was adamant that this was the way she wanted to go, and wasn't happy with me questioning it.
I feel bad, but it is how I feel. Was I wrong to bring it up? I just feel so strongly about this.