I could hazard a guess that younger readers don’t read other peoples’ handwriting much?
I didn’t even notice it was a problem, but I am middle-aged (I actually like personal writing and I dislike the industrial repetitiveness of fonts. I especially dislike fonts for comics designed to look handwritten but that lack human variability).
One way to improve would be to trace a font like comic sans or ames (I'm not actually a font connoisseur). The tracing would be for keeping the kerning and spacing good, not for literal cloning. You can do your own style, but your style itself still needs to be legible.
You can also make your own font file from your hand writing.
Pinch zoom didn't work on this website in Firefox for Android. This would also compound the existing problem.