Besides VCS unfriendly, the storage space for all the additional space characters provides little utility. For the most part, computers are reading CSV, not humans (though we might scan them).
I presume the parent means changing the data s.t. the max length of strings in a column changes; this would cause the padding after that column to change, so as to keep subsequent columns aligned & looking nice. This doesn't play well w/ VCS diffs, as a bunch of data that isn't changing semantically is now changing syntactically, and a simplistic textual diff reflects now that syntactic change, whereas a human reader would want to see the semantic change.
Now… most diff tools also have options to ignore whitespace changes, for cases like this.