This happens at my BigCo job too. We literally are not allowed to give any official recognition of the incredibly hard work and immense talent of our contractors. "Contractors" - the human beings we work with day in and out, that build amazing products, that we joke with, share holiday photos with, wish well when they're sick, urge to take a break every once in a while, who seem to work well into what should be their kids' dinner time or bedtime. But because they get paid differently, they're treated like surfs. They always are forgotten in company e-mails, they always have a harder time accessing services, since they don't get a company laptop they're left to go through some RDP interface to use a machine on our network, they don't get the same vacation days we do. I really hate how they're treated.
And let me guess, when it comes to the types of work assigned to them they are not treated like the types of completely fungible hourly workers that you would expect from the type of treatment you describe?