There is a difference between being alone and being lonely.
As a freelancer, I am alone, but I am not lonely, i.e. feel the need for constant companionship. I guess it depends on your personality.
Freelancing is far from a lonesome occupation. I've been working from home for almost 10 years now and I never get enough time for myself. There are always e-mail, instant messages, new tasks to think about that I long for a day where I just take a walk in a park or drive by myself.
It's true you don't have colleagues bugging you while you work, but I find that very annoying. When I work I like only to have some music playing in the background. Even if somebody revs a car in front of the house it gets annoying. I really don't know how those companies with hundreds of people in one room get anything done. Like that it's difficult to stay focused and it would time at least 2 times more time to do anything.
If you are a newbie then it's good to have more experienced people around if you have questions, but with Google it's really difficult for me to understand why bother someone else with simple questions.
Irene has part of it. It depends on your personality.
The other part is that not every freelancer feels lonely because of the things they do and who they're with.
A married or "spoken for" freelancer, I HOPE, doesn't feel lonely!! As a married man / freelancer, most of the time I just feel interrupted!! Thankfully the interruptions were mostly caused by gaming or time to eat. So it's cool !!
A freelancer that travels might never feel lonely. For example, a PC repair technician. As a formerly travelling PC repair technician, I used to go all over the place fixing PCs, laptops, etc. I found it rather hard to feel lonely when I met that many people. While doing some PC repairs, I even ended up as a DJ at a nearby radio station which caused me to meet that many more people. The only difference now is that my PC repair work just shows up at my place at random. Same stuff, vastly less travel. Works for me!!
Still ended up meeting people from all around. Even from other countries. Things like this don't really leave me with much in the way of feeling lonely. Working as a freelance writer on this website just added on to it all.
There are cases where the person in question doesn't get out much due to freelance work or even perhaps another reason including injury. That's where the personality kicks in. Some people don't even care. They see it as they were talking with others somehow, eventually. It doesn't even bother them in the slightest. They might even have a hobby they like very much so they don't even notice. They're fine. Others that see it differently might start to feel lonely. No one there with them.
And of course, anyone could be surrounded all day long and still feel lonely. Nothing new there.
Freelancing = Loneliness? Of course not. It's all in how you look at it. Someone could try their best to convince you that freelancing is some sorta lonely life. Truth is, they're quite busy trying to convince themselves that they've helped someone. For all they know, they could be causing more damage than good.
"Hi... here's a friend of mine I wanted you to meet. I think he / she is lonely. Go hang out with him / her". All the while you're thinking "Hello, nice to meet you. Welcome to my fresh slice of hell. Enjoy your stay. Try not to die of boredom because my friend never bothered to find out that I like your friend over there more than you. Note to self.... punch current friend in arm + get new friends that bother to ask first"!!
I'd call it solitude; alone but not lonely.
But if you find it lonesome working alone, find welcome distractions like a TV or stereo running on the background (if your type of work allows it), a pet around (as long as they don't type things on the keyboard jklbnmtyu...), exchange warm greetings or engage in short chats with family members living with you, and join a group of other freelancers at shared offices (I thought of this but it's more expensive than an apartment's rent).
I'd say yes, Freelancing = utter Loneliness. Having worked almost a decade in a regular job I had "company" whenever and wherever i worked. I could chit-chat with colleagues, crack jokes, had lovely lunch gatherings, discuss issues and other stuff with peers in a regular job. But now that I'm a freelancer, i find all of that gone & missing. For most days and most times, we freelancers work in "isolation". We have no people to accompany us, which might make us feel remote. Though of-course you'd have the "virtual" world to accompany you and give you the false impression that you're connected and have company.
So yes, freelancing is a very lonely job and it leaves you not only alone but also lonely.