@Yiwei3 There's nothing "too strict" about expecting a guest to be honest about their intentions or enforcing guest count- there's nothing you've done wrong on that front. Other suggestions building on what Andrew said, is to not take one night bookings, as those are the most likely to be the "party" bookings. You can also adjust your setting to require up to 3 days advance notice for bookings, so you don't get any last-minute "Hey, I know, let's book an Airbnb for a party tomorrow night" guests.
If you don't already, make it very clear in your listing info that any guests not accounted for on the reservation will not be allowed on the premises, and if more people are found to be there, it will lead to the entire reservation being cancelled then and there. Repeat this in a message to guests when they book.
You might also consider not having self-check-in, if your schedule would permit you to meet and greet on arrival. You can get a sense of whether they are likely to need some watchful vigilance on your part, or it's just some quiet middle-aged couple on holiday.
Be aware that these scammers who lie about hosting a party tend to look for new listings, assuming, usually rightly, that the host is inexperienced and they'll be able to bamboozle them. As you build up more reviews, up your price a bit, and get established, you'll be less targeted for this type of activity.
And ask a friend or family member who looks like someone not to be messed with, if they would be on call to attend the house with you if ever have to confront this kind of scene again, so you're not on your own. I have a friend people call on like that- he looks like some bada** straight out of The Godfather, even though he's really sweet and non-violent. But you wouldn't know that to look at him.