Looks like someone has a secret and they aren't sharing 
. I had a look at core/svg and most of it is created by Inkscape. That should mean those parts have the same problem. However when I tried it, they don't because the text isn't in the svg files (except for the part label that is there as a text item). All the pin numbers and internal labels aren't listed as text. It looks like there is a way to cause the text to be rendered without using the text directive xml so font sizes aren't an issue and we just don't know what the secret is. There is also a bug report that has a manual text edit workaround for this problem but I haven't tried that yet (and it is from a couple of years ago and may no longer work).
Peter Van Epp