With the field bunching up before the hairpin as the race was restarted on Lap 27, Stroll went into the back of Ricciardo, lifting the RB car up in the air and causing terminal damage to the Australian's car.
Ricciardo was pushed into McLaren driver Oscar Piastri, who also sustained damage that compromised the rest of his race.
The stewards swiftly exacted judgment on the incident, fully attributing blame to Stroll. The Canadian received a 10-second penalty and two penalty points, bringing his tally up to seven for the past 12 months.
"We determined that Car 18 ought to have anticipated the pace of the cars in front, particularly Car 3 and should have prepared to brake accordingly," the FIA race stewards judged.
"Had it done that, it would have avoided the collision. Hence Car 18 was predominantly to blame for the collision that ultimately led to Car 3 having to retire from the race."
Stroll's actions were also slammed by Ricciardo, who said the Canadian's lack of responsibility "made my blood boil".
But Stroll said he felt the stewards should have taken into account that the field bunched up very quickly, which ended up being caused by his team-mate Fernando Alonso locking up his front tyres.
"I think it's just because of the fact that I hit the guy," Stroll said when asked by Autosport why he said the penalty was a joke on his team radio.
"I got a penalty because of the end result that I hit Ricciardo, but it's not like everything was normal and I just slammed into the back of him.
"There was a really odd concertina effect that I would have liked to see the stewards take into consideration maybe a little bit more.
"Someone braked at the front of the pack and then everyone stops. The car in front of me just stopped from like 60 to zero. It was one of those stupid incidents.
"I was in his gearbox and ready for the restart, and just very unlucky. We were having a good race so then so it's a shame."
Stroll said he was otherwise on for a decent result as Aston is still finding it hard to compete with McLaren, Ferrari and Mercedes.
Alonso finished seventh after trying to make a three-stop work, but his progress through the field in the final stint halted when he got up to seventh.
"We were on for eighth or ninth, so pretty normal for where the car is," Stroll said.
"We're not bad, we're making progress. We seem to bit stronger on a Saturday than a Sunday.
"We have to keep bringing upgrades and trying to get a little bit quicker every weekend, but we can fight."
