1) Incentives, residential ISPs obviously have a far bigger incentive to try and monetize your traffic.

2) No lock-in for hosting products, way more competitive hosting market, hosting companies have incentive to provide better service than residential ISPs.

3) Residential ISPs tend to have a far bigger attack surface and less trained staff. I hacked many of the worlds biggest ISPs and hosting companies, the ISPs were always running Solaris from a decade ago.

One reason is that you and your ISP are almost certainly under the same jurisdiction. So your ISP is more likely subject to coercion by your government, compared with VPS providers in other jurisdictions. Further, you can choose VPS providers in jurisdictions where such coercion will not likely be successful.