It's good to have a bit of diversity and options, especially when they're all trying to be compatible.
Also has the added benefit of reducing the need to use compilers like Intel's (not sure on current benchmarks) but I really wouldn't want to ship something for AMD CPUs with Intel's compiler.
https://en.cppreference.com/w/cpp/compiler_support and embedded compilers, or more legacy like platforms aren't listed.
> It's good to have a bit of diversity and options
It can be consistent to hold that those two statements do not hold in this case. GCC requires that developers uphold certain user freedoms (i.e. compiler extensions must be free software). Clang allows user's freedoms to be more easily violated.
It's fine if you want to hold those two opinions, but if you state them as if they're the only opinions, that's not great. If you don't acknowledge that they're predicated on beliefs such as "user freedom isn't important to the expense of software improving in other ways" (or such), then of course you'll have trouble understanding why one might view clang/llvm in the negative light of effectively enabling "GCC, but without GPL".