What you mean is the most difficulty, which is not the same as the numerical block hash. The natural numbers less than 2^256 are a total order, but difficulty is a partial order on block hashes.
What are you talking about?
You deleted my example; that may be the source of your confusion
Here, look at it in fixed-width font, with some emphasis:
0xffffffffffffffffffffffffffff0000
0x000000000000000000000000000f0000
See how they have the same number of trailing zeroes? For any target you choose, either both will match it or neither will. Yet these two numbers are not equal. Therefore difficulty is creates a
partial order on block hashes. On the other hand "less than" is a
total order on block hashes.