Quote - It appeared that "Constructive Criticism" was equated with "complaint."

It essentially is a complaint. If you look in a thesaurus, you will find the following alternative words for "Criticize":

• disapproval
• flak
• bad press
• quibble
• fault finding
• carping
• niggling
• nitpicking
• pestering
• nagging
• pan
• knock
• slam
• snipe at.

"Constructive Criticism" makes it sound "softer" than what it really is.  Which is why there is an art to presenting it so that it doesn't come across so harshly.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi