Thing is regardless if they change it, they still made the original content, meaning they already broke the law. So they still can get arrested regardless if they change it now... That goes for all the other Devs worried about getting arrested also...
True, although by that logic if you've ever committed a crime you may as well keep on going because you're already going to jail.
The reality isn't quite that simple.
By deleting the old work, it does become more difficult to directly link it to them. Especially years after the fact, whereas if they find the development files on the dev's computer, its pretty open and shut. So that's one factor.
And if they are arrested at a later time they can point to the fact that they discontinued it as changing their ways which can possibly help in court.
Secondly, if no one has come after them for their game yet, it does mean it is less likely someone will come after them for it if they discontinue it. But if they continue, it is running the risk of drawing attention at a later time. That is why you don't necessarily keep committing crimes just because you already committed one crime; maybe you won't get caught for the previous crime(s), but if you continue, you keep on risking getting caught by drawing unwanted attention for new crimes in the future.
As weird as it may sound, I think the fact that he barely changed their designs makes it worse because if he was worried about being arrested, these changes don't really help much so it just ends up feeling like he erased all the progress for nothing.
Eh... as the entire thing is about "looks like they are underage" this does help, by increasing the bust sizes and height of the girls, saying they are possibly 18 becomes more plausible - although as I said, having some pubic hair would probably help there as well. I do agree that resetting the progress is annoying, but well, it's up to them. Could be that maybe they just felt like it as well.
Interestingly Dumb Koala talked about this once, she (I think DK is a she) claims that she doesn't see her characters as under 18. She even had one where the character is based on a real life model, who is over 18, but looks very underage (it happens, there used to be an entire porn mag devoted to it called "Baby Face", 18+ models that could pass for under 18). DK apparently just likes doing lolita characters.
As for "they did it just for the money"... while possible, I am not going to leap to that conclusion. I find that accusation is thrown around a lot - usually by people that aren't donating a single cent - and in most cases you find that the dev isn't really making that much money on the deal. Sure, some people do have a pile of subscribers, and some of them rarely make any updates, but they are the minority. Most of the devs simply aren't making a lot of money on it. Most of these things are passion projects they are doing for their own fun and hoping other people will enjoy, and any money they make is a nice bonus, but they aren't going to be quitting their day job any time soon.
And well, frankly... if he did do it for the money... welcome to capitalism.
I checked the Subscribe Star for this, and he's making respectable money per month, but I doubt he's getting rich off it. What I find interesting is that he wants to hire someone to help him do it, that right there is a reason to upage the characters. By bringing someone else in he risks colliding with their sensibilities, and that they could turn him in - or that he simply will have difficulty finding someone to help do something with characters that appear that young (this was reported as a problem with Insexual Awakening, the hired artist was really uncomfortable with the apparent age of the characters - so for IA2 they went to the crappy Koikatsu models instead, and pushed the apparent ages down to maybe 8, while still claiming they are 18+).