Alonso, reprimanded for his dangerous actions, had already finished the race in second, behind winner Sebastian Vettel.
Three cars on their slowdown laps - including Lewis Hamilton's Mercedes - had to take evasive action to avoid Webber and Alonso's slow Ferrari.
"There's not much I can say about that,'' Webber said.
"It's very frustrating, but the stewards have made their decision. It's now going to compromise my race in Korea, which is tough to take.''
But according to former driver and TV commentator Martin Brundle, Webber was filthy.
"Just spoke with @AussieGrit, you have no idea how p***** off he is about a 10 place grid drop in Korea for catching a lift with Alonso,'' Brundle posted on Twitter on Monday.
The penalty did not sit well with Red Bull boss Christian Horner either, who said the image of Alonso giving Webber a lift was "good TV'' and did not deserve such a harsh punishment.
"It should have been dealt with by a fine or a slap on the wrist,'' Horner told Autosport.
"Perhaps, in this instance, a talking to the drivers would have sufficed. Ideally a fine would have been better, but I don't believe that is something available to the stewards now.
"It is a shame and frustrating because that puts Mark now on the back foot now in Korea. It is what it is and we certainly can't change it.''
Hamilton, who said the image was reminiscent of Nigel Mansell giving Ayrton Senna a lift home at the 1991 British Grand Prix, admitted he was "really shocked'' by the incident.
"I went to the right of him, but if Mark had been walking across where I went then I would have run him over. Fortunately, that wasn't the case,'' he said.
"It's good for the fans to see and, as long as it's done in a safe manner - you don't stop on the racing line - then maybe it should be allowed for the future.''
- AAP