Thomas was dismissed in the 52nd minute of Northampton’s 30-14 Aviva Premiership win, taking matters into his own hands after Dickinson pulled back James Percival at a maul.
The Saints player was yellow carded for the incident, with Ryan feeling it was just reward for a string of offences at the maul by the home team.
And the Warriors boss, who also saw his side hit by the sin-binnings of Leonardo Senatore and Sam Betty, cut a frustrated figure after the game, feeling Dickinson overreacted after being struck in the face by Thomas.
“We’re just a little bit frustrated that we ended up with a red spoiling the game,” said Ryan, who saw his side suffer their 14th defeat in as many league games this season.
“You’ll go to a tribunal and people will talk about a strike in the face and you’ve got no defence. It’s just wrong, and it is wrong because I’ve seen worse cuddles.
“Let’s watch every week and watch things that are going on and suddenly we end up with that. A big man goes down from a slap in the face. I’d be more embarrassed about that.
“He (Dickinson) got yellow carded for taking a man off the ball, but it wasn’t picked up until he got a slap round the chops. He got a slap round the face and fell over.”
And when a reporter asked Ryan whether he would have gone to ground in such an incident, he replied: “I don’t know. It depends who slapped me round the face.”
Saints boss Jim Mallinder disagreed with Ryan’s assessment and backed referee Wayne Barnes’ decision to send Thomas off.
Mallinder said: “You can’t go punching to the head, can you? It’s something you can’t do.”
Saints continually overpowered Worcester in the set piece, with the maul proving a particularly effective weapon.
They earned a penalty try from one and also saw GJ van Velze go over from another, but Ryan felt they did so unfairly.
He said: “They get a penalty try and they’ve got about five people holding people at the front (of the maul).
“Clearly, the same thing happens again because he comes back and gives (Dickinson) a yellow card for it. There is no way he comes back for a TMO offence or penalises if JT doesn’t react.
“So you end up with a reaction, which is a red card, and you end up with a slap in the face being a red card.
“We’re going to have to go to a tribunal, it’s our captain, and all because nothing gets dealt with.
“It’s not just this time, I’m frustrated that we end up looking at the reaction. There’s a citing proceedure in place and they never cite that (pulling at the maul) ever, so we can never say it’s ever dealt with yet everyone knows it goes on.
“Then, when people try to deal with it themselves, they end up with a red card and it’s disappointing.
“It was a tough day up front for us and I think we were putting in a good shift, but when you go a man down it makes it easy for them. They just keep putting it in the corner and there’s nothing you can do.
“We could have got something out of that. I don’t know what, but we’ll never know now. You end up with two people off the field for not much. A slap and a reaction because of a holding.
“We’ve sat under our posts after a penalty try because four or five guys are holding at the maul, and nothing gets done about it.
“You say to JT to hold your counsel, but we’ve already been under the sticks once (for a penalty try) and nothing gets done about it. It doesn’t get picked up.”