Earlier quoted context omitted.
It's not a conspiracy theory. Could you point to the 'debunking' because I don't see one that contains any actual evidence?. There are lots and lots of public mailing list posts by RMS and other GCC engineers explaining their reasoning for not making GCC more modular. The reasons were political. For example RMS vetoed the first attempts to add support for Java bytecode to GCC because he thought it would allow people…
Are posts from 2001 and 2007 really relevant for this discussion? Look at this for example: http://gcc.gnu.org/ml/gcc/2014-01/msg00182.html The "debunking" in this thread was the confirmation that plugins actually work now because the policies were relaxed in favor of them.
Plugins are only part of the story. Without stable intermedia representations there is still no GCC equivalent to libtooling or LLVM IR. That is by design, and remains true.
No conspiracy theory. Just an ugly truth that some people want to deny.