MAC OS Mojave: Why do the icon texts display unnormally (squeeze and crowd)?
There are likely a few things going on here. Firstly is that Apple's new default font is San Fransisco in Mojave (OS X 10.14.x) and I believe in 10.8 was Lucida Grande. So some of the text crowding you see could be caused by a different font with it's different kerning, etc.

It is also possible, and judging from the screencaps you posted that some of your desktop/folder defaults were changed or reset when you did the upgrade.

If you go to your desktop and select "Show view options" from the "View" menu a window will pop up allowing you to change a lot of the items that will effect what you see on your desktop. You can do the same in a Finder window but I'm sticking with the Desktop here for sake of simplicity.



The things you may want to fiddle with are the grid spacing and the text size.

The grid spacing will move icons closer together and farther apart. So if you have long-ish file names Finder will squish the text when the icons are closer together.

The text size will also affect how Finder shows file/folder names. Bigger fonts will cause the Finder to try and fit longer file names in smaller spaces (grid spacing) and squish the words/letters together. The trade-off here is that smaller font sizes can be harder to read.

In your particular case I would increase the grid spacing and decrease the font size substantially and then see if things are looking better.