I just can't help but notice the thought that doesn't go into a lot of posts on this forum.
As others have stated, it's a big ship with a lot of mass. Like a big truck, going 60-0 in a second is no simple task. Couple that with the fact you are in supercruise at a very high rate of speed, dropping out of that suddenly is going to have some significant effect to your ship.
Just to point out the difference (also completely arbitrary) a big ship may take compared to a smaller. Take 10% of 100 square feet which is 10 square feet. Now take 10% of 1000 square feet which is 100 square feet. Say for instance your ship is repaired at $300 per 1 square feet of damage. That's $300 for a small ship and $300,000 for a big ship. Makes sense to me. There's much more material in replacing 1000 as opposed to 10 square feet.
The wiki also states: "The Python is a heavily armed and well-protected craft, and boasts considerable maneuverability for its hulking size. Despite being exceptionally powerful and potentially useful in a variety of roles, the Python does suffer from exceptionally high operating costs, making it a potentially cost-prohibitive option for many players."
If you're going to be interdicting people on a regular basis, consider using the right tool for the job.