Who is for people

Who is a very handy pronoun. It does a splendid job of showing that we’re talking about a person. 

So why are so many writers using that instead? Why reduce people to the level of things, objects, animals? 
In my view, using that is a bit tacky. (But it has been around for centuries, so it’s not exactly a trend.) 

He leads the chefs that will cook meals on the yacht.
Are you someone that can’t make quick decisions?
The service is for patients that have no support at home.
Travellers that take carry-on luggage save time. 

It sounds much more natural to say:

The chefs who will cook …
Someone who can’t …
Patients who have …
Travellers who take …

When ‘that’ is OK

That works if it refers to a type or a category, rather than the person or people themselves: 

He’s the sort that never says thank you.
They belong to the class that travels in luxury. 

Otherwise, who’s the best!