Pete, it appears that the majority of the public would agree with your ‘summary execution’ view. However, along come the ‘do-gooders’ who mention apparently wrong executions (like Derek Bentley etc) and the whole this ends up in an exercise in mass navel gazing – and nothing happens and nothing changes.
Legal retribution seems to be too hard for lots of well meaning people to cope with – more’s the pity, but there it is and we have to get on with it.