I understand your point. But:
Julia> ?<specialized package>.<obscure symbol>
=> you don’t need to duckduckgo it! 
Without deep knowledge about specialized field you usually don’t understand what is going one anyway. (independently on symbols vs words).
And if there is same mathematics with different symbols - Julia could help to translate symbols from one field to another and unite them! 
I agree, and for generally used concepts I also prefer names, but domain-specific packages could still make good use of various bracket notations. This would of course imply that one would have to know which one is imported to decipher the notation, but that’s a trade-off for more compact code.
I love unicode for readability. I particularly like the humble θ which I use a lot in trigonometrically oriented code, where I have lots of expressions like this one:
Ak[3, 2] = -ξ * (tanθl * cos2θt^2 * sinP + sin2θt^2 * tanθt * sinQ) / sinθt
Oh, and α is vastly more readable than alpha, especially in complex formulae with lots of symbols.
I used to think unicode identifiers were gimmicky and hard to input. Then I thought it would be fun to write math in julia the same way I do in latex, i.e. a prefix key and “a” to insert α. A few lines of code later (Insertion of math symbols in julia using auctex's mechanism by antoine-levitt · Pull Request #42 · JuliaEditorSupport/julia-emacs · GitHub for emacs if anybody’s interested) I couldn’t live without it.
That Quora answer is a bit out there (FUD). It comes across as someone who has only programmed in one language and is confusing a languages particular idioms with fundamental software engineering. Many of the criticisms about the “object-orientedness” of Julia are just not relevant in practical, Julia code. It’s also not very hard to type ?<: if one doesn’t understand a symbols meaning, and most of them are self-explanatory (≠, ≤, ≥, etc.).
Yes, and I definitely agree with that.
My argument is more with people using Unicode symbols “just because it looks cool”, and not when it’s something (like jargon) which can improve communication (within that specialized field, and where it’s easy to know which field the symbol or jargon is coming from)