First, Free Pascal being an older language, it should have a relatively lightweight startup, by which I mean closer to C than Go (garbage collection) or C++ (exceptions? standard library constructors?), among compiled languages.
Now why is it so much faster than C? My bet is that it is because the Free Pascal Compiler performs static linking by default [1]. Therefore, no invokation of ld.so and no shared object lookup. Those all involve syscalls and filesystem interactions.
[1] https://wiki.freepascal.org/Lazarus/FPC_Libraries#:~:text=Ge....