I think all wizkid was saying was that Brent Spiner can choose his career path all he wants, but he shouldn't be able to dictate what happens to Data just because he's the person that played him.
Which is an invalid position for several reasons. For one, he didn't "dictate" it. He was one of the people who made the decision along with John Logan, Rick Berman, and Stuart Baird, and of course it had to be approved by the higher-ups at the studio, just like every other decision in the process of making the film.
For another, he was overtly listed in the credits as a cowriter of the film's story. It makes no sense to say that a cowriter of the film has no right to contribute to the writing of the film.
For another, there is abundant precedent. Nimoy only agreed to do TWOK if Spock would be killed off in it. Then he changed his mind and that decision led to Spock's resurrection. Tasha Yar died because Denise Crosby wanted out. Jadzia died because Terry Farrell wanted out. The Doctor in
Doctor Who gained the ability to regenerate because the original actor who played the role grew too ill to continue, and his successive incarnations have all lived only as long as their respective actors were willing to play the role (with the exception of Colin Baker, who was fired, and Paul McGann, who was in a failed revival pilot). Countless times in the history of film and television, characters have been killed off, written out, or transformed because of the decisions made by the actors who played them. It's a routine practice. It's ridiculous to say that actors have no right to make that decision, because it happens all the time.
And it's offensive to say they have no right, because it wrongly reduces them to mere servants, when in fact they are vital members of the team effort that shapes a character. In prose, a character is entirely the creation of the author. But in stage, film, and television, the actor makes a vital contribution to the creation and evolution of the character. This is especially true in television, where writers come and go but the actor stays with the character. The way a character's personality turns out is highly dependent on the actor. The writers' choice of relationships between characters is shaped by the chemistry or lack thereof between their respective actors. Over time, writers shape their characters to fit their portrayers' personalities and skills. Picard became a more central character than intended due to Patrick Stewart's great presence and power. Worf became a more major character than intended because audiences liked Michael Dorn. The DS9 writers invented the Odo-Kira romance because of the way Rene Auberjonois played his interaction with Nana Visitor. They made Rom a major character because they liked Max Grodenchik's performance (same with several other recurring characters). The Doctor on
Voyager became an opera singer because that's one of Robert Picardo's skills. It is grossly ignorant and absurd to say that an actor has no role in shaping a character.