Honestly I believe that Nemesis is still ripped by fans because of it's box office gross. Had Nemesis doubled or tripled it's budget, fans would be kinder to it. Money can salvation the reputation of a poorly received film.
Take the Transformers movies for example. Nearly everyone rips Michael Bay for his directing and handling of the franchise but each film has succeeded at making $700+ millions. Despite them being poorly written and critics and fans ripping the films no one hates them. If any of them bombed everyone would be on the f*ck Michael Bay bandwagon.
Don't get me wrong, Nemesis has problems. Most have to do with the behind the scenes crew. Berman admitting that Baird was hired to direct and action movie, and Baird ignorantly disregarding all previous TNG material on some crazed idea that it would hurt his idea of what the film should've be. Sacrificed alot of plot and character moments for our crew. Berman gets an equal amount of blame for being the Star Trek Torchbearer/Overlord and not making sure the great things about TNG remained apart of the film. Allegedly he knew NEM was to be the last film but rather than make sure TNG had a definite ending we get the same stupid ambiguous ending he gave Voyager.
I like NEM. In my opinion it's second to First Contact in the TNG Era. Generations i dislike because Moore, Braga, and Berman screwed the pooch with the story and immature handling of that film. INS was garbage they shat out just for the sake of making a movie. DS9 and VOY were doing way more entertaining things during their runs at the same time. Since they were Berman's brain children, I surmise he was more focused on their success than on the success of the TNG films.
With competition in the summer from Spider-Man, Star Wars Ep II, and the overwhelming success from the LOTR and Harry Potter films, combined with the general's public's misconception that Star Trek is "lame". One shouldn't be surprised the film did poorly. $67 million shows that mainly the fan base showed up to watch NEM. The general public chose to spend their money on the mega blockbusters of LOTR and Harry Potter.