Read again. Sony doesn't want to infringe the terms of the license. Other companies do not want to infringe copyright, either.
Pretend that you work for Sony. Your project uses the Linux kernel. You're sure that you comply with the GPL, so there's not much risk in using the Linux kernel. You want to comply, you're taking steps to comply, and someone on your project screws up, you know that the kernel developers just want the additions to the kernel source code released. That's what you want, too, so no big deal.
Then there's Busybox. The lawyers involved with Busybox might use your use of it to demand a look at all of the code for your project, not just Busybox. They might want to look at other projects, too. They might want an open-ended fishing expedition into all projects in all divisions of Sony. Even if everyone, including suppliers, is clean, that would cost too much time and manpower to be worth the risk. The amount of time it saves your project to use Busybox is not worth risking every project in the entire company to an audit.
The GPL has advantages for businesses. Companies can collaborate on software without violating antitrust law. But there are risks, too. No one likes audits. Not by the IRS, not by the BSA, not by SFLC. Audits cost you time and money even when you did nothing wrong. Some people think that the risks of using Busybox are higher than the rewards, even if you fully comply.
Some people are too annoying to buy from, to sell to, to work for, to deal with in any way. Yeah, NetBSD, OpenBSD, and FreeBSD each have a slightly different focus, but personalities also enter into why there's more than one BSD project. Yeah, XFree86 introduced an unnecessary, unacceptable change to their license, but when you get down to it, Xorg forked because of personalities; people in control were holding the project back.
I like the GPL as a license. I like most of the developers who choose the GPL. But in any group, there are bound to be some assholes. I don't know if that's the case with Busybox, but I'm open to the idea that assholes can choose the GPL.