People weren't under the impression it wasn't connected. They have openly said it was not connected. And the plot details that have leaked out (which were eventually confirmed by officially released details, as well as the Sony email leaks) prove beyond a shadow of a doubt that this film WAS NOT tied to the originals. It was an entirely new story, with the original continuity, story, and characters discarded.
If the film is now some how tied to the original films, it happened late in the process, done via rewrites and reshoots, similar to Paramount's patchwork on TMNT when fans turned on that film after it was revealed The Shredder was white, not Japanese, and not named Oroku Saki but Eric Sachs, a character who remained in the film but had all mentions of him being the Shredder cut out.
I say with 100% confidence that it was not Sony or Paul Feig's original intention to tie this movie to original. And if it now is tied to the original (I doubt it, but it wouldn't surprise me), it most certainly happened because fans turned on the film because of that disconnect. That was and is the first and most important reason this film has gotten so much flack.
And if the rumors of this film's quality are true (also wouldn't surprise me considering the terrible sounding plot leak), then this move makes sense. Sony is going to need to get the hardcore, built in fans back, and that's pretty much the only way to do it.
We already know the original film's cast members appear in this film, so tying this film to the original continuity isn't impossible. They could have convinced the original cast to reprise their roles in reshoots, OR they've always been on board to reprise those roles, and it's been a closely guarded secret. Which feels unlikely since it would require Murray to have agreed to play Venkman again, which he so far has been 100% unwilling to do. And, we have an abundance of evidence to the contrary.
But who knows.... Maybe they did get Murray to finally agree, and all the original cast are back in their original roles. If that was/is the case, I'd certainly be much more willing to go see this film. I always wanted new Ghostbusters, I just don't agree with abandoning the old stories and characters to do so.
