Waerea-Hargreaves sprayed water over Leniu, then threw the bottle at him after Leniu took exception to the Roosters prop catching his Panthers opposite Moses Leota with a cocked elbow in the dying stages of Penrith's 30-6 rout on Saturday night.
When referee Adam Gee opted to also send Leniu to the bin, the irate Penrith player appeared to mouth "car park" to Waerea-Hargreaves before marching up the tunnel at Allianz Stadium.
While Roosters coach Trent Robinson described the incident as "good theatre" for fans, Cleary had a very different take.
"It started from Jared. He was just looking for trouble. That was obvious - and he found it," Cleary said.
"(There were) numerous incidents, weren't there? And I think on the balance of probability Jared was probably the one initiating it.
"I don't know, it was a little condescending, I thought. It just was unnecessary."
Cleary also couldn't understand why Leniu was given his marching orders.
"But anyway ... it was probably a good thing in the end, I suppose," he said before admitting he wasn't happy with Waerea-Hargreaves' initial strike on Leota.
"It was very questionable. The way he looked, where he saw him, the way it was cocked," he said.
The match review committee is certain to review the flare-up but Robinson reckons everyone should just "move on".
"It was great wasn't it, for footy? That's why people enjoy watching footy," said the triple premiership-winning mentor.
"There was nothing in it, I don't think, from either end. Like, there wasn't much to it. It was sort of heated there. (But) I don't think Jared did anything wrong in any of (the incidents).
"Guys tried to race out of the line and belt him and that's really unfortunate for Liam (Martin) who copped a hip.
"And then Jared was getting his bumpers up like every guy does in every tackle they run into and copped Moses there. That's a forwards battle.
"And then it flared up. Good theatre. Move on."
Adding to the drama was the sub-plot of Leniu and Waerea-Hargreaves soon to be teammates after the Penrith hard man's decision to defect to Bondi Junction next year.
Robinson doesn't expect any bad blood to linger.
"That's why there was interest there and that's why you get excited," he said.
"You want guys to react like that - and you want those guys in your team."