It should be noted that it might not be just the media that Ainge ignores.
Chad Ford's annual draft tier article is based on info he gets from scouts and front offices. He had Jaylen Brown as a Tier-3 prospect (players without star potential who project as starters), but mentioned that Jaylen Brown and Dragan Bender were the only two players in Tier 3 that had received Tier 4 votes.
So if Ford's intel is correct, that means some scouts/front offices saw Brown as projected as a future role player/backup. This is backed up by the several computer models that suggested Brown would struggle on the NBA level and had the highest bust potential of any player in the top 18.
So it seems AInge and his team ignore all of that and take who they want. And that's fine... but if the info is true, they might have been able to trade down (or up) to get Brown at #8.
It must be tough to be in Ainge's position, though. Because you never know if teams are giving misinformation and feeding the media lies. It's possible, I guess, that a team below Ainge like the Suns were also super high on Jaylen Brown. And perhaps Ainge felt it was best to just grab the guy he wanted and not worry about it. That's how you get teams taking someone like Anthony Bennett at #1 - they ignore what everyone else supposedly thinks.