I do not think security was an issue at this time. I assume you mean this proposal:
https://www.bell-labs.com/usr/dmr/www/vararray.pdf
I like it and it is on my list to implement as a prototype for GCC.
And WG14 takes security seriously, but I think you overestimate the power WG14 has to simply change things. WG14 is supposed to standardize existing practice, not reinvent the language. So you should complain to compiler vendors. Or contribute to the development of open-source compilers.