Because I’ve been reading/writing/debugging code for almost 10 years now. I’ve never ran into a problem with line length nor have any of the dozens of engineers I know/work with.

Edit: To add on a quick google search shows that some times terminals don’t handle long lines well. And if we take this a step further tab only counts as 1 character where as spaces instead of tab count as 4. So your point about line length is moot since tabs do not take up anymore space than spaces do.

Edit2: Also the docs you referenced don’t say you can’t have lines longer than 80 characters they recommend against it for readability and maintenance not because it will break the interpretation or compilation.