If this is an argument it needs to be in contact with the points on the other side. I'm not aware that anyone argues that reporters are entitled to converse with sources in a surveillance-free environment. Reporters physically outside the US do not carry with them an extraterritorial immunity either to local listening allied with the US or to US listening which is comprehensive "outside." Without regard to targeting journalists for interception (which raises additional legal issues and is likely to involve far more prospective legal analysis within the relevant agencies than you are following here), our problems concern the collateral consequences of intercepting communications by a non-US target of interception with a US-placed US-national journalist, a situation in which claims of right against something after interception (unmasking, analysis, legal intervention, prosecution) are at their strongest. The analysis should focus as closely as possible, I think.

National security reporters, reporters who cover crime domestic and international, political reporters—they are professionals, not naive. We can assume they have some counter-intelligence capability, and the intention to use it only when it is necessary to protect sources. Reporters cannot and do not assume that their work product is protected against interception by any other than technical means.