Basically, the Patriots are a tight lipped organization. It would be difficult to gain the trust of such an organization and few have. Reiss has obviously done that and seems to continue to have sources there. This has caused some to accuse him of being a suckup or toadie and I'm sure such accusations keep him awake at night.
The Patriots are not a government organization and have no ethical duty to provide information unless they think it is beneficial to their private business.
In the past, writers like Borges have developed sources by prodding disgruntled players in contract negotiations, or those with bad press elsewhere, basically the worst type of stories for team unity.
He still tries to do it with every contract problem he can find, but it doesn't work because Belichick doesn't rise to the bait and makes personnel decisions exclusive of media opinions.
Some writers would like to have the right to break sensational, poorly sourced, speculative stories that damage the team (tub of goo Tomase) but still get inside information. Good luck with that.
Reiss works to maintain communication and resists the urge for sensationalism. Since 99% of sensationalist scoops don't help the team, the organization has apparently decided they would rather a winning organization with a bad reputation in the media than the opposite. Dissension sells papers and disrupts successful teams, so I like their choice.