A) They are illegal on Earth with orders to be executed on sight.
B) We don't know exactly how long they have left, only that they are close to expiry date. Imagine (we don't need to imagine the movie shows us) how much murder and mayhem they can cause in their remaining days.
They were trying to catch them because I believe they had like rebelled in the Off-World Colony they were working at and had killed either humans or other replicants... that's how they were able to escape and make their way back to Earth.
Anyways replicants were bred to become slaves... that sucks... I can imagine pro-replicant groups... instead of Tyrell building robots, they were 'farming' these replicants which even though are not conceived as regular humans seem to be genetically enhanced humans made in labs so they are regular living beings.
yeah it had something to do with replicants returning to Earth rather than chillin in the colonies
share1. Replicants exist to be used by humans as slave labor in outer space. If they can just roam the earth like anyone else, that makes their status as slave laborers untenable.
2. If they learn they only have a few years to live, and no chance of being let free from the slave-like conditions they're in, that would understandably make them more than a little upset and to seek revenge or at least violently try to escape.
3. I'd assume that people on earth are taught to regard replicants as unfit to live freely among human populations due to the danger they can pose, which in turn would create public opinion in favor of keeping their presence on earth illegal.
They are genetically altered people. They don't want whatever enhancements or weaknesses they have to enter the normal gene pool.
shareThe replicants are supposed to be sentient but not conscious. Those who rebel are considered to be faulty and dangerous machines.
The genius of this movie is that we witness how they become truly human by experiencing emotions and learning empathy and love.
Something the sequel's writers seem to be completely clueless about.
Because they were killing people.
shareThey explain it in a text dump at the very beginning of the movie:
After a bloody mutiny by a NEXUS 6 combat team in an Off-World colony, Replicants were declared illegal on earth - under penalty of death. Special police squads - BLADE RUNNER UNITS - had orders to shoot to kill, upon detection, any trespassing Replicant
The people in the world of the story see Replicants as appliances, not human beings. They see no need for wringing their hands and going "oh noes, but what if da poor widdle homicidal androids don't wike being wetired? =("
maybe they shouldn't have made them sentient then.
This is exactly the trouble were about to have with AI
I think they try to design them with behavioral controls, kind of like Asimovs three laws of robotics, but some of them end up getting too independent anyway and become sort of runaway slaves.
As you can see in the movie, when they go rogue like that, they can be dangerous.