Why is it so hard for you to answer that question...

To answer the question was not hard.  To answer it before I saw it
would have been very hard.

    You failed to answer these several times already,

When you said that, it was 21:00 here.  At that time I had not even
seen any of those messages; they were not in my computer.  They
arrived in my next mail transfer, today at 12:00.  Subsequently I saw
them and wrote an answer.  You will get the answer in my next
transfer, which is likely to be at 22:00.  That will be 25 hours after
the first of those messages was sent.  I regret the delay, but it is
inevitable.

It must be quite common that a person doesn't answer in 2 hours.  You
may not know the details of how I transfer mail; but there are many
other reasons why someone may not answer so fast.  He might be
sleeping, which many people do for 8 hours at a stretch.  He might be
checking some facts before before responding.  These are things you
know about.

So what does it indicate, that just 2 hours after the subject was
first raised, you said I had "failed to answer", as if it were proof
that I am bad, disregarding what you know?

I think it indicates that you are looking for excuses to put me in the
wrong.  If something happens which you can interpret as putting me in
a bad light, you seize on that interpretation, ignoring the other
possibilities.

Such an attitude can be seen in many of the messages on this list.
It is not one you should want to adopt into your heart.