Comment 1 for bug 1838070

This is correct. The essential thing to understand is the kernel's command-line uses space as the separator between options so:

option1=1 option2=2 option3=3
option1=1 option2="2" option3="3 or 4"
option1=1 "option2=2" "option3=3 or 4"

are all identical.

What you are seeing in /proc/cmdline is the *kernel* writing out each option and, when an option contains a space, it surrounds the option with double-quotes.

Consider that the "=" symbol has no special meaning in the context of the command line although individual modules *may* use it to separate key=value options themselves.