If the author can be taken this seriously given his self-professed ignorance, I am probably much more qualified than him to speak about Chinese characters.
There are two points worth disambiguating here. One is whether Chinese characters hinder the literacy of native speakers and the other is if it hinders that for learners. Neither I nor the author have any authority to speak about the former.
As a heritage speaker, I actually only recently learned Chinese to a level where I consider myself literate. My experience was that the characters were not an obstacle, like the author suggests, but an indispensable tool for rapidly learning the language.
To learn any language, it is unavoidable that you need to memorize thousands of new words. Memorizing a Chinese character is not much harder than memorizing a word. However, the magic of Chinese characters comes when you combine them to form actual words.
The vast majority of Chinese words consists of 2 characters, but because each character also encodes meaning, you can more often than not guess the meaning of a word you have never seen before.
Although you can take advantage of common roots for words in other languages, the scale is simply incomparable. For other languages, you pretty much have to memorize every new word you see.
My experience has been that learning Chinese characters may be a higher upfront cost (although I disagree), once you learn enough, you rapidly understand way more vocabulary because characters themselves encode semantic information.
Perhaps it's simply the lack of any cognates between English and Chinese, and a tinge of cultural supremacy, that make people, like the author, think it's Chinese characters that's the root of everything that makes the language difficult to learn.