One of the things Point Allocation gives us is a limit on how much value can attributed to the players on a particular team, based on how successful that team was. Looking at only an individual players, without considering the team results and the contributions of all the other players on the team, can lead to one or many of the players on a team being overrated.
To illustrate, let's for a moment discuss Paddy Moran, the Hall-of-Fame goaltender for Quebec City who played senior hockey from 1902 to 1917, and who will be profiled here in the next little bit. He was a great player (assuming the Hall of Fame voters got it right) who generally played for pretty bad teams. His career senior-level W-L-T record was only 99-107-2. Even though he generally played in leagues with only four to six teams, being below .500 doesn't scream Hall of Fame.
Not only were his Quebec clubs typically mediocre, they were also typically below average defensively. If you're a poor defensive squad despite having a great (or at least very good) netminder, that means your skaters must be pretty poor. The logic is inescapable.
Take the 1908/09 ECHA season as an example. Of the four teams involved, Quebec allowed the most goals. The Wanderers (with Riley Hern in net) had a 5.03 GAA, Ottawa (with Percy LeSueur) was 5.19, the Shamrocks (Bill Baker) were 8.58 and the Bulldogs with Moran allowed 8.83 goals per 60 minutes. As such Quebec gets credit for relatively few defensive points, since they allowed so many goals. Moran, being a Hall of Fame goaltender, gets the lion's share of these.
The two Quebec defencemen were Art Leader and Joe Power, who both had respectable defensive reputations. So they get some points as well, though not as much as you might assign them were you looking at them in isolation. There's basically nothing left for the forwards (Herb Jordan, Chubby Power, Joe Malone and Jack McDonald), regardless of their defensive reputations.
As it happens, of those four only McDonald has anything resembling a solid defensive rep. In this team's case, I think that has as much to do with style and tactics as lack of ability (which will be addressed when discussing Moran and Jordan). But if you didn't start with the team results and work down, you'd want to reward Paddy Moran, and Joe Power, and McDonald and Joe Malone (another Hall of Famer) and would end up giving too much credit for defence on a team that was not very good at preventing goals.