It's impossible for rational minds to comprehend the levels of hatred that underpin actions like this - trying to understand only makes your head hurt.
The only way to stop this kind of hatred is education of children at a very young age, to accept differences in others, and respect the rights of others to live their lives differently.
Since that education has never been forthcoming in UK schools, and shows no sign of appearing any time soon, the chances of it reaching the sort of cultures that these monsters grow up is tragically even further over the horizon.