Chico was shown two yellow cards in as many minutes in the early stages of the game, being given his marching orders in the 16th minute for a foul on Andre Schurrle just moments after he had also felled Willian.
Referee Phil Dowd took his time making the decision to dismiss the Spaniard, and Monk was unhappy with the behaviour of the Chelsea players on the pitch and staff on the sidelines immediately after the second challenge.
"If you go by the letter of the law it is a sending off, but if you do letter of the law every single game then you will get six or seven sendings off a game. The disappointing thing was that [Dowd] looked like he signalled straight away 'no' - as if to signal it didn't warrant another yellow," Monk told reporters.
"Then their bench and manager surrounds the fourth official and their players surround the referee and then the red card comes later on. It makes you wonder, doesn't it? But I know Phil, and he is an honest guy. I don't think he responded to the pressure. If he says it was him giving himself time, then it is him giving himself time. But the circumstances make it strange.
"It's not great when people are asking for the ref to dish out a red card, but what can you do. It happens, and you trust that the ref was strong enough to deal with all that."
Monk refused to heap too much of the blame onto the shoulders of Chico but did acknowledge that his defender should have been experienced enough to avoid a quickfire second yellow.
"I'm not disappointed in him, but he is an experienced pro and he should have used that experience in that situation," he added.
"We have all been in that situation where you have been booked, and especially if it's early on, you are then treading on a tightrope for the rest of the game. The harshest punishment is getting sent off and Chico got sent off."
The defeat leaves Swansea just three points clear of the relegation zone with four games left to play this season.