It's not the same thing for the same reason that a shiny billboard for an ad right outside your bedroom window that you can't not see every time you look outside is not the same as a text ad on the first page of a book you want to read.

A text ad on the first page of a book is not a slippery slope to a billboard right outside your window.

I use a Linux terminal everyday. I completely forgot it has any ads at all until reading this thread. I have to put conscious effort to find where the ad is.

It would be impossible for a daily Windows user to forget their OS has ads.

My 2 cents at any rate