But there is still a real difference there. One is via a code & compile and the other is via a config. Whichever way there is still difference there.
Yes, but as it is people use different config options when running Bitcoin Core and those are not considered to cause fragmentation, making this change via config would allow for people to use different outbound connection count options without having to maintain and test their own fork.
Having to maintain and compile a separate fork means they have to run code that is less well tested than it could be especially since the core developers actively refuse to provide any assistance and encourage others to not help people making these modifications.