Because Christians are generally speaking quite ignorant of the Old Testament, and not infrequently the New as well. Every religious Jew on earth is well aware of this, and if you read the two versions side-by-side you'll see the differences are stylistic and not substantive--the shade of difference between "honor" and "love" or "remember" and "observe" is just not that great, though our practices often are explained as owing to these distinctions.

If you are looking for something about the Bible to be upset about, you can certainly do a lot better than this.

to be honest, that is the first result I found looking on google for "ten commandments jews"[0].

Sure, as another (apparently deleted?) comment said, if you take them as a whole you more or less can respect 80% of it across a few major branches.

But they are inconsistent enough that if I tell you one by number there's a 80% chance that you won't be able to understand what I mean unless you know my religion, which is the case i replied to.

[0] I first found out that what the roman catholic catechism taught to me (in rome :) as VI, "do not commit impure acts", is different for jews.