The way i see it is different tbh, since Joyboy haki still capable of making Imu's down kneeling.
Its similar with Kaido Oden PTSD since its coming with direct contact. Hence why i think Haki could still injure Imu.
Top 6 at that time didn't had haki as strong as Joyboy.
Plus remember all the top 6 got a whole lot stronger after God Valley.
Even Rocks who is unstoppable at that time imo, is not on Joyboy's level of Haki.
I do agree that DF is the key here to defeat or cancel out imu's power, but the point where the debate start is when u claim that Haki can't injure Imu hence why guys like Zoro or Others can't and will not fight imu, while we see on FB that the Top 6 only used haki but still can fight them even tho it didn't "damage" Him.
Oda might gonna make Haki relevant again with some bs explanation or such to make them capable to fight imu with haki. Cuz the way i see Haki is the same as DF who amplifies their user main style of fight