That's just one person's opinion. You should form your own instead of copying and pasting someone else's. Besides, your link doesn't work.
While this guy's analysis makes sense, I believe that my theory is just as valid. I have reasons too...
The fact that Walter owned a Great Knife (found in the storage room for Walter's corpse in Room 302) explains why James only ran across one knife in the entire game. Both men, who were murderers, had their own psychological burden to carry. Assuming you acquired The Great Knife in SH2, the weapon itself almost becomes this bizarre manifestation of the oppressive guilt that James experiences (or in Walter's case, his self-appointed duty to reunite himself with his mother) and it's cumbersome nature only reinforces the old metaphor of "a cross to bare." Needless to say, both James and Walter had their own "crosses" to bare.
Aside from physical proof, more damning evidence for my little theory comes from newspaper article found in the trash of the apartments. According to the article, Walter witnessed a "red demon," who is of course a/the Pyramid Head, before murdering Billy and Miriam. If what the fellow you linked to says is true, then he would have have had
six Pyramid Heads following him by the time he got to Billy and Miriam, his seventh and eighth victims, instead of only one. His killings didn't occur in a single, fail swoop, so he must have felt the guilt from his six previous victims individually. Now, assuming what this analysis said is true, he would have had a veritable army of Pyramid Heads stalking him at all times, as the analysis assumes that James has one Pyramid Head for each murder. After that, Walter kills three more people, but is only convicted for Billy and Miriam's murders. His eleventh kill, his Assumption, works out perfectly as he can kill himself before his trial and fulfill his Assumption rites. Cue the murders of SH4, Walter is in spirit form, blah blah blah. Now, I'm a little foggy on the subject, but I believe Walter was spotted dragging a large object (a Great Knife) up the stairwell to Room 302 before (or maybe during, I can't remember when) his final ten murders. Anyway, his personal Pyramid Head must have still been alive, as he obviously had to confront it to obtain the knife. Had there been ten (give or take, depending on when he returned to Silent Hill to retrieve the knife) Pyramid Heads, one for each murder, stalking him around, I highly doubt he would have escaped Silent Hill alive; he did have to drag that ridiculously heavy knife around, after all.
My point being that it seems more logical (to me at least), that one Pyramid Head would be assigned to a person, rather than one per person per sinful deed. However...
Many other theories of Pyramid Head abound. For example, some people think that they are the innumerable minions of Samael, sent to Silent Hill to punish sinners. Stemming from this theory is the belief that every Pyramid Head James sees is different, rather than him being chased around by only one or two. Others think that they act as neutral guardians, protecting Silent Hill's secrets from outsiders, while some think that they aren't guardians or punishers or anything of the sort, and instead are malevolent spirits whose sole purpose is to drive humans mad. Some think that they are only in James's imagination, while others think that Pyramid Head and Valtiel are one in the same, and are permenant residents of Silent Hill instead of visions.
No one can really say for sure what he/they is/are, and that's part of the charm of Pyramid Head.
I think our inner fanboy/girl is showing, Ann. Let's see some FF fan delve
this deeply into the psychological lore surrounding Sephiroth.
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