Why Were They Drugged?

they were drugged for the lulz

many events in this movie don't make sense, but thinking about them interferes with the fun

Dr. No was protecting Honey's virtue from James. Murder, torture, and espionage were acceptable on his island, but the good Doctor drew the line at pre-marital sex.

I wondered the same thing. What made the drugging even stranger was the "trickery" aspect of it. Bond and the girl had already been captured and Bond was handcuffed; if Dr. No had wanted to knock them out for a while he could have just injected them with something while they were restrained. Instead, he chooses to slip something into a pot of coffee, leave it out for them, and then hope they decide to drink it.

The only way I can explain it is that that Dr. No enjoyed playing some sick psychological games. Let 'em think they're somewhat safe--Give them a lavish room, offer them a nice breakfast, then: "Gotcha!" The coffee was drugged! Kinda silly but it's the best I can come up with.

"We put the drugs in the coffee and they took the bait. They're safely out-cold."
"What? I didn't tell you to do that. I told you to invite them to dinner!"
"Oh, but I thought... It's just that usually you want the coffee drugs to-"
"Usually, yes, but not this time."
"Okay, but usually-"
"Did I tell you to drug them?"
"Well, no, but-"
"SO THEN DON'T DRUG THEM!"
"Stop yelling at me! You're always criticizing me! My therapist says I should be more assertive, and this is not okay in the workplace!"
"I'm feeding you to my magnified piranhas."

Why did they slip Sam Spade a Micky in "The Maltese Falcon"?

I figured it was to search James for possible weapons or communication without chancing him resisting.

Dr No wanted to see if he could get them addicted to drugs