Nobody "gives" set amounts of memory to their processes at all, so this thinking is backwards to begin with. The vulnerability is legitimate.
Various other systems also limit with things like /etc/login.conf on FreeBSD. There is also /etc/security/limits.conf on Linux for non-systemd stuff.
Limits for memory usage/open files/things of that nature are natural. You don't want one runaway process to cause the rest of your system to OOM.