I don't believe all politicians are the same, although every political party has its bad apples.
I think it goes further than that. I believe our system encourages "chancers". Once an election is won and a big majority obtained in the FPTP system, nobody else's vote (opinion) matters.
Most people in the UK want a stable government and country with minor tweaks to suit themselves of their beliefs. We currently don't have that. We have a government which can do what it wants and people feel helpless about stopping it. It's like having a ten pound note burnt in front of your eyes while your hands are tied.
I'm not surprised people are cynical, but I also believe that change can happen if enough people stand up and make their voices heard. The backlash over the "Paterson Affair" shows that governments do occasionally have to listen. Complacency is an enemy of justice.