A disagreement on any of those questions reduces to either incorrect reasoning or differing preferences. People having identical preferences may be uncommon, but I don’t think you can say it means someone isn’t thinking.
The issue discussed isn’t whether it is a problem that some people might think (or prefer) alike. The issue is (emphasis mine):
Ideally, everyone should be thinking alike
A disagreement on any of those questions reduces to either incorrect reasoning or differing preferences. People having identical preferences may be uncommon, but I don’t think you can say it means someone isn’t thinking.
The issue discussed isn’t whether it is a problem that some people might think (or prefer) alike. The issue is (emphasis mine):