I think people are hoping that you might see that you do have inbuilt prejudices; we all do, and facing up to them has been one thing that makes it easier to then make yourself do something you're afraid of doing. You might choose to really examine your own beliefs about solo travellers and what you honestly think of them - if you really truly do not think anything bad of them, or don't even notice them, then you can start applying that to yourself and it might help you overcome the fears, because you know that people won't be thinking that of you. Or, you may realise that actually, yes, you do subconsciously think that people who are on their own are sad or can't find friends or whatever, and this will help you to change your thinking. I have often found that when I tell myself "of course I don't think people who are xxxx are horrible, but it's just that I don't want to be like xxxxx myself, it's me that I'm judging etc" - it turns out that I'm not really being as honest as I might like to think I am, and that actually, I can't say that it's not OK for me to be like that without admitting that I am unwittingly judging someone else. I try to convince myself that it's different, that I can have different standards for me and other people, that if I'm harsh on myself it doesn't mean I'm harsh on them, but in the end, it's not true. To develop real compassion, I've had to learn to extend it to myself and other people equally; to recognise where I judge myself, and where I judge others, even if I don't want to believe I do. It also makes me realise that other people might perceive me as judging them, when I say negative things like how much I hate some aspect of myself, or how self-conscious I feel. And because I care about how they feel, I try to change that, rather than just writing it off as them choosing to take it badly. It was actually a kind of wake-up call to me, to realise that I was revealing some subtle judgement, even when I thought I was actually just showing things I didn't like about myself or being self-deprecating!
And that has helped me start to get over fears of things. It hasn't worked completely, and is definitely still a work in progress. I'm afraid of a lot of things. But perhaps the difference is that it's something I actually want to get over, because I'd like to be able to do things like travel alone. If you really don't want to go - and it sounds like you don't - then you might as well scrap the whole thing now. I think people are responding as if you maybe underneath do actually want to go, if you could get the courage to do it, and by telling you these experiences, they are giving you coping mechanisms to allow you to go through with it.
But if you don't want to go, and are just looking for validation of that decision, then that's fine too. You don't need to. If you think you'll hate it, then don't bother. You'll waste the money on the flights, but at least save the money on the accommodation, food, etc., and you'll be happier not having to do it, if that's really what you feel.