At first I thought that you linked to the wrong poll by mistake.
The last question does show more "favor" than "oppose" for installing back doors in encrypted systems, but the first question shows much more "oppose" than "favor" for reducing encryption to help government agencies. The second question shows that more people want tech companies to protect customer privacy than to cooperate with government agencies to fight terrorism and crime.
So people want encryption back doors that don't reduce encryption and don't require tech companies to cooperate with government agencies. Of course "we can have all the good stuff and none of the bad stuff" is a common delusion among government agencies proposing encryption back doors too.
Yes, since the operational outcomes of the first and last questions are the same, the main notion this poll really confirms is that people in general don’t understand cryptography.
c.f. also the recent Australian prime minister who claimed that legislation can override mathematics.
The last question does show more "favor" than "oppose" for installing back doors in encrypted systems, but the first question shows much more "oppose" than "favor" for reducing encryption to help government agencies. The second question shows that more people want tech companies to protect customer privacy than to cooperate with government agencies to fight terrorism and crime.
So people want encryption back doors that don't reduce encryption and don't require tech companies to cooperate with government agencies. Of course "we can have all the good stuff and none of the bad stuff" is a common delusion among government agencies proposing encryption back doors too.