kishi wasn't forced into anything, because he's been doing stupid kitten years before the ending. he replaced hinata's potential for love, made sakura hold onto a love that made no sense, and had naruto chase after a guy who hated his guts. the ending is just the accumulation of all the kitten he's been spewing in this manga.
But how much of that might have resulted from someone whispering in his ear? I'm not absolving Kishi of anything, what you say is true, but I'm more in the middle of the spectrum. I kinda believe want you say as well as what was said before. It's hard to me to believe that it wasn't forced, but I also acknowledge that he caved. So he is at fault, but outside pressure might have played into it as well, if that makes any sense.