First of all, thanks for contributing to the FreeBSD community
While I'm not a ports committer I'm quite confident that I can explain the reasoning behind some decisions.
Submitting a patch does not require you have commit access, it does however require you to offer maintainership if it's a new port unless agreed upon by a maintainer team (edge cases). How to submit a patch is documented in Porter's Handbook and it refers to SVN because that's what the tree (FreeBSDs) still uses, it will eventually switch to git (a few months left) however. There's no hard requirement to use SVN however, you can use a VCS you prefer but it needs to be able to generate a patch/diff file (avoid .shar because it's pain to work with) but it is implied that you as a submitter know how to generate a patch using your preferred VCS.
Mentoring will usually be offered if you for a period of time (usually at least a few months) submit patches that are consistent. They don't need to be perfect all the time because we all do mistakes but the majority should at least work as intended and get accepted by a committer or maintainer if it's an existing port.
And with all due respect John, looking at your PR at bugzilla you need to dial down the agressiveness of your replies, it's not going to help and I think raised questions are vaild and please keep in mind that people can make mistakes (such as misreading about commit access).
I can't see anywhere were you're being told off, however "we" do not want "random forks" in the tree because it gets confusing, may cause compatibility issues such as packages clashing with eachother and they
usually bitrot quickly (ie broken packages and a maintaince burden). While (open-)motif isn't dead it's not a very a active project looking at the commit history but unless your fork has breaking changes have you tried upstreaming your work as this is the preferred way to go instead of carrying forks or custom patches in tree?