Many recruiters are sending their emails from a system, not writing them by hand. They look they came from a template, because they did.
Add to that that when that recruitment system was implemented, the recruiter probably didn't bother updating/customizing the default templates, making their emails just the same as everyone else's.
Add to that that when that recruitment system was implemented, the recruiter probably didn't bother updating/customizing the default templates, making their emails just the same as everyone else's.