Misinformation about Starvation Mode and Fat/Muscle Loss

I just wanted to clear a couple things up that have been bothering me, sorry if I offend anyone! :)
I get bored and google random things to pass the time.. and one thing that keeps popping up is "Starvation Mode" where people are claiming that eating less than 1200 calories a day will halt your weight-loss progress. First, I don't even know who came up with that number, how does EVERY person need to eat 1200+calories a day to LOSE weight??! From what I understand of basic calories in calories out is that the less calories you eat, the faster and more you lose weight.
People are trying to claim that if you go below this magic number, you will cease to lose weight because eating too few calories will cause your metabolism to slow down.

Let's assume that eating too few calories will cause your metabolism to slow down. Even that being true (and I'm going to make up some numbers here) let's calculate weight loss assuming no exercise:

Person A needs 2000 calories a day.
Person B needs 2000 calories a day.
Assume 3500 calorie deficit to lose 1lb.
1. Person A is dieting and is worried about starvation mode, so eats 1200 calories a day. Her metabolism does not decrease. She has a daily deficit of 800. 3500/800=4.4 days to lose 1lb.
2. Person B is dieting and is not worried about starvation mode, so eats 200 calories a day. Her metabolism slows by let's say 25% meaning she only needs 1500 calories a day. Her daily deficit is still 1300 calories. 3500/1300=2.7 days to lose 1lb.

I know my math isn't the best haha and some of the numbers are made up just for comparative purposes. BUT 25% is a high estimate for how much her metabolism would actually slow down based on research (google it I don't feel like adding a link).

So even if your body does go into starvation mode, you will still lose faster in it, then out of it!
Another thing I hate seeing all over the internet is that if you lose weight too fast or eat too few calories your body will hold onto fat and you'll lose muscle.
Umm, what?
Your body STORES fat so that when you starve (either on purpose or because of famine, body doesn't know the difference) it can use the fat stores to survive without damaging muscle tissue.
The only time the body stops using fat stores and begins using muscle tissue is when the body reaches 5% body fat (men) or 10% body fat (women). So unless you are severely underweight with that body fat percentage or less, your body will use up the fat first!

Just tired of the misinformation being spread all around the internet, had to rant a bit and clear things up haha! But I'm no doctor so what do you think? Do you agree or disagree and why?
Love to hear from anyone with any opinion :)

xoxoSasha