Hammers fans weren't keen on signing Barton, he claims.
The Burnley midfielder was linked with the Hammers after his release by Queens Park Rangers a year ago, but many fans were against the proposed move.
But their reasoning, Barton claimed, was somewhat hypocritical, given recent well-publicised incidents involving a section of the club's support.
The 33-year-old said: "I was watching the football during the week and I remembered this time last year when I was linked with signing for West Ham.
"There were certain elements of their supporters [who] basically didn’t want me to join the club based on the fact I’d had one or two moments of controversy in the past - to do with fighting and so on and so forth.
"I witnessed them smashing up Man United’s team coach and just was chuckling to myself at the hypocrisy of West Ham United fans."
Barton's Talksport co-host, Adrian Durham, was quick to point out that Wednesday's events were not representative of all West Ham fans.
And while the former England international agreed with that statement, he was unable to get his head around what happened, on what was supposed to be a momentous occasion in east London.
"No, that’s absolutely fair," he added. "It’s a small minority but it certainly looked like there was a couple of thousand of them.
"I didn’t get it. They were saying goodbye to the ground. Why would they want to sully that?"
Barton, who previously played for Manchester City, Newcastle United and Marseille, eventually signed for Burnley last summer and helped lead them back to the Premier League at the first attempt.
The Liverpudlian was even named in the PFA's divisional team of the year as Sean Dyche's men ended the campaign as champions.