So you don't believe it's enough that the parents have already been taxed on the money that they are saving to help their children do better than they did, but you think the children should pay a second tax? This is not tax-free money we are talking about, it asking two parties to pay tax.
Assuming that the parents are above the lower tax rate threshold (to be able to afford to have >£275k in assets) then that means they have probably already paid ~40% tax on the money they wish to pass on. This means that after all of their hard work, only 50% of this money can actually be inherited.
Most parents work to provide for their children, and if they are in a position to help them, then why should they be hindered? I cannot understand the mentality of someone who thinks that every generation should have to start from scratch and shouldn't be given the opportunity to have a better standard of life.