No, it's quite the opposite, it is a morally bankrupt society where people are too cowardly to do the right thing and remove these cancerous non humans entirely from society. They're not people, and it is very wrong indeed to inflict them on actual humans to deal with in any capacity - morally bankrupt and cowardly to make such a call.
And there is almost zero risk of wrongful conviction, however if you are going by stats (which is what you are doing when you make that part of your argument) the almost microscopic number of people who would be wrongly put to death is massively outweighed by the enormous benefits of removing these non human societal cancers from the gene pool, from the lives of real humans and giving true and fair justice to their victims.
As you are making a cost benefit analysis by mentioning the microscopic number of wrongful deaths by execution, the cost benefit analysis is hugely skewed in favour of executing these cancerous non humans.