Clearance on hold, hold for release

Up until the other day, when I heard "Hold for Release" it was after I
had copied, read back and accepted my IFR clearance, squalk code, and
had received ground control clearance to taxi to the departure runway.
It rarely involved waiting more than 10 minutes before being cleared
to taxi, or takeoff.

Our airport has a clearance frequency, which I contacted first on the
day in question after engine start. The controller said switch to
ground frequency to receive my clearance, which I did. I repeated
"ready to copy" and received my clearance as filed except for a squalk
code and departure frequency. I asked for the code and frequency and
was told "Standby, Hold for Release".

I figured, OK, there's a slight delay. So I asked again in 10 minutes,
as was told in an abrupt manner, "Hold for release", but nothing else.
So, after waiting another 30 minutes with the engine running I called
again for my squalk code and departure frequency. I was pretty
surprised by the response. The controller said, almost as a
reprimand, very angrily, "What are you still waiting there for! You'll
get your squalk when you're ready for takeoff!" Then and only then did
he issue taxi instructions to the active, which I complied with.

After getting into position for the run-up, he said to contact the
tower, which I did. Tower asked me how much time I needed to get
ready, and I said, "About 5 minutes, but I still need a squalk code
and departure frequency." Then, tower said, "standby, hold for
release." After a minute he came back with the squalk code and
frequency, and I was cleared to depart.

So, my question is, what exactly does the term "hold for release" mean
within the context of the situation I've described? What could/should
I have done differently; i.e., said "ready to taxi" after hearing
"hold for release" the first time, expecting to receive the code and
frequency from the tower when ready for takeoff?

Thank you very much.
Hap