To signal potential open source contributors that there is no danger of being sued for their work. Too many vendors have used the fact or even just the accusation of reverse-engineering or other non-EULA-compliant behaviour to suppress OSS.
I don't see a connection to "outsource tool development to some other company".
If I commission some work from another company, this company doesn't receive, modify or extend my software under the standard EULA. They do so under our contract.