It's an interesting strategy in part because it means a lot of the people encountering him are probably not aware of him in other online spaces, they'll only see him when republished in sources they already read, and they might not ever work their way back to his blog.
On one hand I'd be very worried about dilution of the message, misinterpretation, etc... On the other hand, it's enabled Doctorow to get some of his concepts into much wider cultural circles than he otherwise would have access to, so it's hard for me to criticize it too much.
And I think that Doctorow also has a talent for figuring out how to frame his ideas in a way where the conclusions stay the same, but it feels like he's reaching those conclusions by arguing specifically from your individual starting position and ideological base. His essays tend to (again, imo) feel tailored in a way where regardless of the context or regardless of where the essay is published, it'll have this vibe of "I'm on your community's side and I'm saying stuff that you all are going to nod along to and agree with... and therefore X/Y/Z."
Pros and cons to that approach, but it makes him accessible in a way that many other political writers aren't. So it's not too surprising to me to see his writing show up in Conservative circles as well as Liberal ones, I think it just kind of shows his talent for subtly reframing political discussions depending on the context.