Hayden, whose arrival at the club was protracted by nearly a season after red tape initially prevented him getting a work permit, admits:
"It took eight months for me to get there, and now it has all come kind of crashing down again after only really being able to play about a year.
"It is kind of sad because I made a lot of friends at West Ham, and I wanted to stay at the club to fight for a spot.
"But the manager has his own way of thinking and made it clear I wasn't in his plans - so really there was only one way for me.
"I had to move somewhere, because if I had stayed I wouldn't have played at all; I had no choice as I wanted to play regularly."
Hayden insists there are no hard feelings towards Glenn and adds:
"You have to accept these things in football; it is his decision, and I suppose football is a business now.
"At the end of it all I obviously wasn't in West Ham's plans and they wanted to move me on as soon as possible."
Hayden was, of course, involved in the infamous incident at the players' Christmas party when Hayden 'watered' a plant pot, but does not think the incident counts against him.
"I would hope not," he says, "because it is what you do on the pitch that counts and Glenn said that had nothing to do with it; the club stuck behind me."
Glenn himself confirms that is the case and says:
"I am sure he will regret for the rest of his life what happened, unfortunately, but I don't think there is anyone who has not done something that they are a little bit ashamed of in their lives; anyone who hasn't done something like that can start throwing the first stones.
"But there were no stones thrown because we have all done things we are not too happy about, and we have to live with that."
Back to Hayden, who adds:
"I only played seven games last year, and, to be fair, had one not so good game which was Charlton; but in all the rest I felt I did well.
"It is Glenn's decision and his planning for the future; there is a really good squad there and I think West Ham will do really well in the years to come.
"The younger ones are a year younger and a year wiser - Mickey, Joe, and Jermain have so much ability and played a lot of games last season.
"Trevor has just come back after a great World Cup, I thought, and there was plenty of support back in Oz for him."
And, crucially, Hayden believes that the Hammers might be able to improve on last season's seventh spot to clinch a place in Europe.
"I think they can finish higher than seventh next season; I will always be looking out for their results, because they are my buddies," he insists.
As for the future, and a reunion with Harry Redknapp at Portsmouth, he says:
"Harry is the one who brought me here and fought for me; he made me welcome when I came to West Ham and has done so now I am at Portsmouth.
"Harry is his usual self, and Shaka is here as well, not to mention Toddy - but I don't speak to him a lot as he doesn't speak much English.
"H has bought some players, including a striker from Juventus, and there is talk of Ginola coming over.
"I don't know much about Portsmouth, to be honest, though they didn't do so well last year.
"But there is good backing and a good support base - and maybe we will be playing West Ham next year!
"It is a new start for me and my wife so let's hope it is successful; dropping down a division does not bother me because at the end of the day I want to play football."
Hayden, who was sold to Portsmouth for a small fee, understands why no Premiership clubs chased his signature and he explains:
"You can't expect people at the top to come in for me when I have not played regular football for two years, and this will let me play regular football week in, week out."
He hopes the transfer will allow him to get back in his national side.
It was his lack of appearances for Australia - largely, it must be said, through injury - that led to problems getting a work permit in the first place, but now he is married to a French national he has no such worries.
Nonetheless, he is desperate to return to the Australian fold, and says:
"The main aim is to get playing for Australia again but it is not easy to get in the Aussie squad now as so many players are playing in Europe every week."
And a final word?
"I still wanted to stick it out at West Ham, really, but it was clear I wasn't going to be in the first team plans.
"I made a lot of good friends in London, including the boys at the club, and it is sad to leave because I have a lot of good memories from the place, even though I was only there a short time - they are a great bunch, and I wish them well."