It’s not stealing when you willingly allow someone to use it however they want. OpenBSD writes: “We want to make available source code that anyone can use for ANY PURPOSE, with no restrictions. We strive to make our software robust and secure, and encourage companies to use whichever pieces they want to.” If your goal is to polish something like OpenSSH until it’s as good as it can be, the world is better off when robust and secure software spread, also into proprietary systems. When companies use OpenSSH, it does not take away anything from OpenBSD, they are not competitors.