Last time I looked is was neither immoral or illegal to buy an investment property.
And we've also got to remember when it's your home "value" goes out the window...you want it, you want it
Realistically speaking, the issue for me is that a lot of people are not being homes, they are buying first foot on the ladder type places which they don't expect to live in for longer than two or three years because of course they will trade up.
There are numerous references to a figure suggesting that 40% of newly built properties bought last year were built by investors. While that's not actually immoral, you'd have to question a situation where the people who want to buy houses to live in are priced out of a market where almost half the properties being bought are bought people who don't need them. As for the unoccupied figures it would appear that we're building a lot of houses to satisfy demand which is not based on demand to occupy. That's a bit skewed.
Most of what we're building of late is tailored more towards the short term "few years and we'll trade up" and investor market, rather than on long term planning. I don't think that's good morally and I suspect that there are a lot of new apartment blocks which won't see the end of their 99 year leases.