Tbf, the post did say Mihawk can defeat a lot of fate "character".
Key point "Character" not "Servant", which can means Fate normal human Characters like Taiga, Uryuu, Issei, Byakuya and their like.
Of course, this is just me hoping that what SB really means lol
Nah, that's not what SB means, they actually do believe Mihawk can tear through most Fate characters including Servants.
Trust me, I've been on that site for 3-4 years and been scoping them even longer, it's well known as shit they downplay virtually everyone in the Nausverse ultra hard to absolutely ridiculous degrees(I even brought up how they act like Quetzalcoatl's Piedra Del Sol is just Country level and can be "taking down by TSOs" as if they can take down a freaking Star).
EDIT: To put it in an easy way, they still believe Servants can't destroy Planets because Siriel keeps tossing in Da Vinci's point completely against what Da Vinci meant later on... which would only affect Nasuverse Earth and JUST Nasuverse Earth and thus, Planetary is somehow beyond their reach despite it very, very much isn't.
Like it's not a joke to say they will pretend Soujuuro Shizuki, Shirou Emiya in any route and Rin Tohsaka can and will lose to anyone in JJK worth their salt despite their feats utterly eclipsing JJK by leaps and bounds because "Nasu is consistent in making the characters seem just superhuman compared to other writers" when that's such blatant horseshit if anyone has ever looked at Tsukihime or Witch On The Holy Night for more than just skimming through and downplaying.
So yeah, they aren't wrong in putting that there because it ISN'T incorrect and let me put it on the table:
Miyamoto Iori, Miyamoto Musashi and all of the other Sword Saints/Masters would bury the shit out of Mihawk and Zoro casually as fuck.