And today's dumb post of the day award goes to...
Or... a film rated PG-13 has a larger audience demographic than an R-rated film, meaning more potential box office revenue. Is that such a difficult concept for you to understand? Director's Cuts have been the way to show the movie as intended. Theatrical cuts are to maximize viewing audiences and showings.
To other points you've tried to make, Blade (which is also a Marvel property) came out in 1998 and was rated R. Please elaborate on how Deadpool was an original concept.
Avengers Age of Ultron was a standalone sequel. The first part of Marvel's two part movie, Avengers Infinity Wars doesn't hit theatres for another two years, and has already been done before several times (Harry Potter, Hunger Games, Divergent, Twilight), so it's not like they pioneered that concept either.