Exactly what I said. It has nothing to do with his ability to play football. Nobody shared your opinion when Archie stood up for Eli. Many fathers have done this. Yet Deion is being targeted for it. Only one reason I can think of.
For me, it's Archie didn't make himself a high profile public figure. He didn't constantly seek public attention. He didn't very publicly say controversial things. Archie also didn't assert himself into the Giant's decisions or criticize them publicly after Eli was drafted. It's very likely that Deion will do both of those things to whichever team drafts Sanders.
Archie Manning also didn't play for the Falcons and then shun the Saints to sign with the Cowboys, so there's that fan element as well.