The competition of legal entities for our attention seems to be one of the major reasons of chronic stress and mental illness in the west, so the answer is yes.

This conflates the ends and the means. They're different and both deserve consideration.

Some reading:

https://simple.wikipedia.org/wiki/The_end_justifies_the_mean...

https://saylordotorg.github.io/text_the-business-ethics-work...

> What if you replaced the word marketing with attention?

Then you would be making a different argument. Marketing and attention are not the same thing: the former is one means to the latter. Marketing is grabbing attention by force, which could be considered unethical; attention by itself can be consensual and organic.