Ontario needs limit on guest and their stay.

It’s mind boggling to me how tenants are allowed to have guests over without limit on number of guests or length of stay.
There will be people defending this, but can we just make a law where it is appropriate?
Imagine you’re renting out your 4 bedroom house. I move in, then rent it out to 10 people, you know what, let’s do 15, cause who needs a living room and dining room. Let’s say $400 each, that’s $6,000 a month right there. I pay you, the landlord, $4,000 and pocket the rest. What are you gonna do about it?
Wait a minute, you can’t do that ,that’s subletting. But what if I told you I’ll be “living” there too? I mean, I put some personal items there and changed my mailing address. I’ll just be a “guest” at my friend’s place, who also rents indefinitely.
There you go $1,500 a month extra, easy.

But wait there is a fire code limit on how many people can live in a unit. Mind you a 2000 sqt home fit 15 people and still within code.