I completely agree with this person.
Not every schizoid is the same, also. For example, I am aromantic-asexual and aplatonic. But I am capable of developing familial emotions for people after a (considerable) amount of time. Some schizoids may differ, such as being capable of platonic but not the others, or some other nuanced scenario.
Some schizoids simply are just as asocial as the stereotypes, but that doesn't mean they're devoid of any feeling or interest. The "lack of emotion" or "mechanical behaviors" commonly stereotyped with schizoids is generally due to emotional dissociation--its a defensive mechanism formed from trauma.
As for another take on the interests, while it is true that many schizoids lack hobbies completely, that's not always the case. For example, I have always had an interest in writing since a very young age. Most of my other interests can either be incredibly short lived/fleeting, or permanently etched into my internal phantasy world. But also, I have pretty bad writers block problems.
Many schizoids have friends, even if they're aplatonic or do not desire closeness. Not all, but enough. It would also be a good idea to be familiar with our terms and coined terminology. For example, a "safety person," "interest person," and "stock person" are common schizoids terms used on tumblr and maybe other places (I wouldnt know, I dont have other social media). Not everyone uses them, but they can provide context on how we see relationships.
I heavily agree on the /schizoidvision blog, I am not familiar with the other one, and I'm going to go ahead and suggest /schizoid-hikikomori. I also suggest reading /schizoid-hikikomori's pinned essay that he wrote (though, be warned, his blog occasionally contains graphic imagery) along with the books he references in the essay.
(Note: replace the / with an @)
"The Divided Self" by RD Laing is a very popular and commonly referenced book written by a psychologist that explains schizoid personality. A personal recommendation is "The Empty Core" by Jeffery Seinfeld.
It is also important to note that schizoid personality is inherently the severation between the external and internal world. So whilst schizoids may be heavily disconnected from the external world through dissociation, it is commonly observed by psychologists that we have a rich inner world with a highly active imagination. We may not desire external relationships, but many of us do phantasize about fake ones in our own minds.
Why? Because self-control and autonomy are extremely important to us. Schizoids tend to especially avoid relationships that make us feel like we lack either or both. Oh, and as an off handed comment, I notice we get irritated easily (judging by schizoid vents that I read).
It would also be a good idea to look at the differences between covert SZPD and overt. Personally, I'm covert, so I am really good at masking and mimicry. Overts may have a more difficult time and are more susceptible to the "flat affect."
As final advice... just find schizoid blogs and look at their thoughts and what they're interested in, and how they view things along with their online behavior. I know one schizoid with a bug hyperfixation, one dude is super into philosophy, and another with a peculiar hyperfixation on Mario. Then there's me, the loser that likes Genshin Impact.
We're not too hard to find if you look in the right places. Oh, and if you want to see external behaviors, you could probably find youtube channels of schizoids talking about their experiences. They're difficult to find, but I promise you, they're there.