Why are some recommendations made

Is there anywhere in all the huge collections of words about WP where the explanation is given for why something is recommended?

For example, when doing a security checkup in the iThemes plugin, the result is to disable the theme editor and one is told (in a round-about-way) to gain access to the file system so as to be able to edit themes, etc.

BUT, WHY?

NO reason is given for what I suppose is someone’s idea that the editing of themes using the WP admin interface is a security risk.

I suspect I’ll receive many replies telling me to ask this question of the plugin developers as opposed to this forum — but I ask you to realize this question is only a specific case of a more general question about WHY things are recommended.