That's one obscure way of looking at it. Another is the fact that a lot of people have accrued value in property purely for living there and doing nothing. Perhaps rather than IHT they should apply CGT instead so you don't pay anything on the value of the capital of your original investment! You could also argue that it is immoral to become rich through the hard work of your parents rather than your own endeavours!
This, absolutely.
Both points are spot on.
Most inheritance tax is paid on untaxed capital gains on housing etc (so it's absolutely not double-taxed income as lots of people seem to argue).
Similarly, as a middle class house-owner I see no reason why my kids should get a massive windfall when I die, through no particular merit or effort on their part (on top of all the advantages they already have in life by virtue of having reasonably well-off parents), when other kids who just happen to have the bad luck to be born into a family in a council house or with no wealth, get nothing. It's one thing to argue that people should keep the fruits of their labours; much harder to argue that they should leave it to their kids, who've done nothing to earn it.