What exactly was Soong trying to achieve?

[Mister Spock]

He wanted a sexbot. Everybody trying to build androids just want sexbots.

That's the history of scientific endeavour in a nutshell. The first caveman to light a fire almost certainly did it in order to be able to see a cavewoman's bottom in the dark. And how quickly do you think the first caveman to invent cave painting went from pictures of buffalos and antelopes to big boobs and fannies?

 

[Mudd]

Indeed; there is evidence that the earliest examples of musical instruments - Upper Paleolithic flutes and drums - were the innovations of male nomads who hypothesized that chicks would dig musicians.

 

[Qonundrum]

You know, at no point should we be thinking that Noonien Soong is a good guy.

His wife left him because of his singlemindedness & abandonment. Lore is not wrong about him in Brothers. His 1st obligation should've been to the intelligent being he brought into the universe, to suffer with an emotional disability, but instead, he just abandoned him, & moved on.

^^this

The colonists had felt Lore was "too perfect" and felt discomfort as well - which could lead into one hell of a tangent as well if they are actual sentient life forms, since one would think the fellow community might try to help - hence the definition of the word? But if Data is a bona fide sentient life form, then by extension so is Lore and that's where it gets good. Soong wanted his inventions to be accepted as bona fide sentient life forms, ironically. (No wonder Lore is annoyed in "Brothers".)

There's nothing wrong in making Data, but he easily could have fixed Lore, what with both being virtually identical. One little firmware augmentation and Lore would be Data, without the slot for the emotion chip upgrade. Indeed, why not just fix Lore, which would have taken less time, instead of making a whole other android that looks the same but doesn't twitch or have distinct emotions or contractions (unless the script, director, and/or actor screw up)?

Granted, Soong is making his androids to his image...

Maybe Soong is also attempted metaphor for Roddenberry in some ways too. But there's already a thread on that: https://www.trekbbs.com/threads/roasting-roddenberry.303641/
(Some do say TNG was Roddenberry's attempt to reboot the franchise in his way and undo as much of TOS as possible... /metaphor )

He had no basis for assuming that his "Limit Data's emotions" scheme would work to make him any better off than Lore. Soong is a reckloose. He even has his own legit Bride of Frankenstein running around out there

Given the number of times Jean-Luc was threatening deactivation or disassembly of the same life form he called sentient but never once threatened to kill or use a mind probe on any of the biological gooey crew...

 

[Mojochi]

The colonists had felt Lore was "too perfect" and felt discomfort as well

No one felt Lore was too perfect. That was Lore giving misinformation. The concern they likely had was that he was dangerous, & unstable

There's nothing wrong in making Data, but he easily could have fixed Lore, what with both being virtually identical. One little firmware augmentation and Lore would be Data, without the slot for the emotion chip upgrade. Indeed, why not just fix Lore, which would have taken less time, instead of making a whole other android that looks the same but doesn't twitch or have distinct emotions or contractions (unless the script, director, and/or actor screw up)?

I don't know how easy it would've been to fix Lore. It took Soong the better part of 3 decades to get Data's emotion programming right. Clearly an already actively malfunctioning one could present as much a challenge or more, & his point seemed to be that such time would be better spent working with an upgrade, rather than a fix. Ultimately, when he refers to Data as "The next logical step" he meant in the research. He chose advancing the research over tending to a failure. Sadly, that failure was an intelligent individual who got neglected as a result

Given the number of times Jean-Luc was threatening deactivation or disassembly of the same life form he called sentient but never once threatened to kill or use a mind probe on any of the biological gooey crew...

Never. Picard never threatened Data with disassembly or deactivation. The one time the subject was even broached (in Clues) Picard is only threatening Data with court martial, but he is cautioning that such an action, in that case, might end up with others looking to do so. He is not suggesting he'd take that action. He doesn't even really want to go through with the court martial. He is expressing his concerns that it might come to that on its own, if Starfleet thinks Data has endanger an entire crew, which is not the same thing as Picard condoning such an action being taken, & that dialog exchange gets misconstrued that way... often.

Apart from that, once Data's rights have been established, Picard hasn't ever been in favor of having Data shut down or pulled apart for any reason, beyond the occasional need for him, just like numerous times with the other crew members, to be stunned or knocked out temporarily.