I've submitted this as a help ticket to report is as a possible bug, but if anyone else is able to confirm that tables display this way as well I would appreciate it! I've tested it both on my organization's hosted Canvas instance and on https://resources.instructure.com/
For anyone who is unfamiliar with the Canvas styleguide, I recommend requesting an invite to Canvas Hacks https://community.canvaslms.com/thread/2140 or or putting /styleguide after your Canvas URL; for example: https://YOURCANVAS.instructure.com/styleguide
If you make a content page and copy the code from your styleguide, see if the tables in your content page have the same amount of vertical padding as the tables in your styleguide. Below is an animated GIF screenshot showing how tables on my content page do not match the styleguide (not enough vertical space between table rows in the default ic-Table class, even ic-Table--condensed appears to have more space).
Also, I do realize that many styleguide items do not work in the Rich Text Editor as noted in other styleguide documents on the Community, such as here Using the Canvas Styleguide: Icons, but I seem to remember this one working... hmm.