I certainly don't think that I'm the only person on UHH who knows electronics - in fact, there are many here and several other EEs and extra class holders. I have responded to you with the most basic facts of electricity, Ohm's law.
So what part of my statement(s) do you specifically disagree with?

Reading your post again, you seem to be referring to the voltages and currents from various "wall wart" power supplies. These are simple supplies, typically consisting of a transformer, a bridge rectifier and a filter capacitor. They rarely have a voltage regulator (but may). The output voltage is determined by the secondary voltage of the transformer and the load. The current rating is typically the maximum current that can be supplied at the rated voltage. The actual current depends on the load resistance AND the internal resistance of the transformer secondary - they appear in series. If you want to prove Ohm's law to yourself, get out a "wall wart" (unregulated) supply, your DVM and a handful of resistors, and start loading the supply with different values. You can then monitor the voltage and current and easily calculate the internal resistance of the supply. You'll notice that as you increase the load (decrease the resistance), the voltage will drop and the current will rise, exactly as predicted by Ohm's law.