It simply means that powerful and rather undemocratic pro-Israel lobbies, especially in the US (and it rubs off on every UK prime minister I can think of) make it impossible for governments to speak out.

That does not stand up Steve.
Countries like Ireland, Sweden, France, Australia, Canada, etc. do speak out against US policy all the time.
If they really believed Israel guilty of heinous crimes they would say so and act accordingly.
The FACT is they do not.

Well, in terms of what I perceive to be outrageous human rights abuses, I could (but won't) bemoan the amount of defence Israel gets here

That ignores the FACT that a huge number of countries with a far worse record of human rights abuse are NEVER criticised by all you Israel bashers.