Pirelli motorsport boss Paul Hembrey has questioned the F1 rule that allows drivers to change tyres under red flag stoppages.
F1 fans were robbed of a thrilling end to Sunday's Monaco GP when Sebastian Vettel was permitted to swap his aging rubber for fresh tyres just six laps from the end of the race.
The German was tenths ahead of Fernando Alonso and Jenson Button, who were on newer tyres, when Vitaly Petrov crashed, resulting in race control red flagging the grand prix.
The stoppage allowed Vettel to put on fresh tyres and, when the race restarted, he was able to comfortably keep his rivals at bay, taking his fifth victory of the season.
"I can understand there is a safety consideration but I am thinking about it more from a fans' perspective to be honest," Hembery told Autosport.
"I've had a lot of people shout at me from the boats around the harbour and say, why were they allowed to change?
"It took away something from the race - and the big question was could they have lasted? That is what we were all asking with six laps to go and that was going to be the excitement: would Sebastian hit the (tyre degradation) cliff?
"We don't really understand the rule, and maybe we need to ask the teams why they think the should be allowed to change tyres.
"The race distance was still the race distance, it wasn't extended. The cars had stopped and there had been a safety car anyway. I don't really understand why they are allowed to change tyres, but maybe I am missing something."
The Pirelli motorsport boss added that it was a "shame" as up until then the leading trio being on different strategies had made for an exciting Monaco GP.
"Overtaking is at a premium here, so having the strategic element and such varied strategies, one, two or three stops, gave it an extra bit of intrigue," he said.
"I think it was a bit of a shame with the red flag of course, because if they hadn't changed the tyres, then they would have had to fight to the end as they were all on different strategies, and the tyre wear and life was very different.
"It is such a shame we were not able to see the finale of the strategy game that had been played."
