Not exactly, no. I'm not concerned about using antitrust authority to police open source. Regular copyright law, combined with usefulness of open source project

Not exactly, no. I'm not concerned about using antitrust authority to police open source. Regular copyright law, combined with usefulness of open source project, is enough and should work (or fail) on its own. What I think does merit some review is a corporate policy to build a market or platform around a widely-used protocol (whether or not technically open source), then extend the protocol so that you break other implementations of whatever you're doing. For example, let's say you build a SIP telephony service that's extremely popular. Then you introduce some proprietary elements so that all traffic that you route uses SIP + your proprietary extension. Suddenly everyone has to pay your toll to use SIP, unless they want to give up access to most of the market.