That is unfortunately completely wrong. Your example password is extremely easy to crack. Password crackers nowadays don't brute-force letter by letter anymore, but are based on wordlists. They also take into consideration that people like to append special characters and numbers to the beginning or the end of the password. Humans are way too predictable to be trusted to generate randomness; this is a scientifically proven fact.
But it's not the special characters that make the difference in this example password. It's the phrase. Systems typically match words, but not phrases.
The system can combine "water" "salt" "sugar". But combining as a phrase "water" "with" "salt" "and" "sugar" is more unlikely.
Of course, this is just an example, and I'm not saying it's invalid, just that it's less likely to happen.
As you said rightly, the systems normally check letter by letter. Therefore, it is more likely to pick up a combination of random letters than a sentence that is understood by a human.
Which do you think is easier for an automatic system to find:
"1McY1aGwc8jvFtA."
or
"My2YearOldCatLikesYoWalk."
Both are equally strong, but the second option is much more difficult to be recognized by an automatic system than the first.