It sort of is and isn't true. CPUs are designed to make certain programming models work very well, and they've done so at the costs of making other kinds of programming paradigms work well (as compared to, say, a GPU, which wants a programming model for which C and C-like languages are clearly ill-fitting). So it's not a wrong statement if you think of it as "designed for C-like languages."
But if you're using it in the sense of "C is a privileged language in terms of its connection to hardware architecture, " well, C isn't, and that statement is patently false. There's not a major difference between C, C++, Rust, Zig--even going as far afield as bytecode languages like Java and C#, or fully interpreted stuff like Python or Perl, especially as far as computer architects are concerned.
(And in the sense of "this is the language that architects care most about for tuning performance," I think that's actually C++, simply because that tends to be the language for the proprietary HPC software that pays the big bucks for compiler support.)
But if you're using it in the sense of "C is a privileged language in terms of its connection to hardware architecture, " well, C isn't, and that statement is patently false. There's not a major difference between C, C++, Rust, Zig--even going as far afield as bytecode languages like Java and C#, or fully interpreted stuff like Python or Perl, especially as far as computer architects are concerned.
(And in the sense of "this is the language that architects care most about for tuning performance," I think that's actually C++, simply because that tends to be the language for the proprietary HPC software that pays the big bucks for compiler support.)