Windows x64 and security

In reference to this post
I perfectly understand why it was closed, since the question of the OP was clearly answered. However, in my view it raises another question. Now that we understand that no security solution can modify the kernel in Windows 64 bit, and that the developers of security solutions have to rely on APIs provided by Microsoft, I would like to know if the level of security is comparable with what we have on a 32 bit system with the same security solution (in this case CIS), or if the level of security is significantly degraded because it cannot modify the kernel and has to rely on a workaround. In other words, is the user of a 64 bit system significantly as reliably protected by CIS as the user of a 32 bit system. If it is not the case, is it fair to say that 64 bit systems have to be avoided for the time being for users for whom security is important (this having to be balanced with other advantages brought by Windows 64 bit, but these are another topic).

Any thoughts anyone ?