I have just compared the “gross” bubble from the article with my “real” bubble. Made a screenshot of both and used the ios color picker.

“Gross”: #7EC170

Real from the bottom of the message reel: #65C466

Real from the top: #73E173

No issues with contrast in either case. Also keep in mind that those color hexes will slightly vary depending on where exactly you decide to pick since bubbles are filled with gradients.

Not sure where author gets his bubble from but in real life they look as “good” bubbles at the bottom of the screen that makes me think the article itself is gross.