Hard forks allow for cleaner code fixes than soft fork kludges.
This is a common misconpcetion and lie spread by BTU fanatics. SWSF vs. SWHF is a very trivial different and SWHF does not fix any kind of "soft fork kludges" (as they don't exist in this context).
try reading code and documentation
in a segwit HF there wont be any "upstream filter" tier network.
the blocks will just be blocks that everyone recieves.
EG just a upto 4mb block.
not
a 1mb block inside a upto 4mb block that gets stripped to 1mb.
everyone will get the upto 4mb block.
segwit done as a hardfork where everyone is part of the same level playing field peer network.. non of this soft fork tier network crap