Yeah, weird...'contractor' as an employment category by definition means that a company doesn't deal with you as a regular employee. What exactly did these people think they signed up for?
Employers make it a point, often, to blur the lines. Contractors, by government definition, get to choose their own hours, their own tools, they must be compensated dynamically for their expenses. When I was a contractor I felt that I was an FTE with shittier benefits; I was told where to be and when to be there, my tools were dictated to me, and if I ever asked about purchasing something to do my job better I was assuredly told, "no". I think, "I feel like a second class citizen" adds up to, "I was duped into FTE with none of the benefits."
The healthiest thing to do, as a contractor, is to draw the line in both directions. Be very familiar with your contract and if an employer asks you to do something outside it, reply with a very clear "I'm sorry but that's not in the scope of my duties. If you need me to take that on we can renegotiate."
It feels shitty if you're of the mindset that you want to solve problems and not play legal games, but Lord knows the employer isn't incentivized to not try and wring every ounce of work out of you they can get for below-market FTE prices.
Not that you're wrong...but (speaking from second-hand experience: my ex was [0] a contractor at FB) this sort of thing is a fabulous way to lose your job. The company will do whatever it has to do to bring the hammer down on any nails that stick out, and they've got enough legal and financial resources to get away with it.
You are 100% correct. Unfortunately, that attitude is needed because it also serves as an early-warning fuse for that relationship; the in-built assumption in my advice is the contractor has the freedom to leave and contract with someone else. If the employer tries to extract work from you without compensation, they are abusing the contractor relationship and giving a clear signal that it may be time to take one's labor elsewhere.
The word "contractor" is overloaded. Many folks, apparently including the Nintendo workers described [1], are actually not contractors, in the 1099 sense, under the law. Instead, they are W-2 employees of Company B, which is hired by Company A. Company B is legally responsible for offering them benefits, but they don't have to be equal to Company A's.
[1] "The specific charge, as first reported by Axios, is levied against both Nintendo of America and recruiting firm Aston Carter, which hires contractors for various administrative and customer support roles at Nintendo." https://www.ign.com/articles/former-nintendo-employee-accuse...
That's not "contractor" being overloaded, that's the definition of contractor not growing when companies invented this scheme. It's the same circumstances a contractor runs into, and often the contract company is running really bare minimum, awful benefits.
It's not like Google, for example, is looking to hire you if you don't have one of the couple-dozen college names they're into on your résumé. But if you get hired by a contracting company that posts you at Google to do a contracted task, you'll get to put that "Worked at Google" experience on the résumé and get a leg up.
Plus some people (falsely) assume that the environment will be great because the company has a great reputation. At the interface of the contractor level, that varies widely. I had to go to bat at my old office because I randomly showed up on the weekend and found out all the contractors were working in 85-degree heat in an office building; the building turned the A/C off on the weekend to save power, and nobody had thought to ask it be turned on when we moved a whole contracting team in to work weekends.