Raul no this is not a standard practice and is most likely the result of improper installation of electrical attic wiring.
Running wires through your attic.
If you can run it across by stapling it to the rafters you can avoid the insulation thing.
The following links will assist you with your electrical question.
The attic wiring should be protected and secured to ceiling joists or other wood structural supports.
This is usually a moveable piece of drywall or plywood that covers a rectangular hole in.
Start by inserting a long wire through the hole you just drilled a disassembled wire coat hanger works well.
Find your attic access.
When running along the joists keep them 2 above the ceiling.
After you窶况e run the wires through the clips you snap a plastic cover over the entire assembly.
Yes this should be corrected and it would be good to have the wiring and all the circuit connections inspected as well.
As nickblake says run cables on top of ceiling joists but route in a low part of the loft i e.
Where the cables can t be walked on.
You simply mount a small plastic clip to every other joist.
If the attic is inaccessible you have less a worry about protecting the wires than you would if it were a storage area.
How to run wire through an attic step 1.
If a lot of wires are already hanging from the bottom of the floor joists you can run the wires through raceways that fasten to the bottom of the joists.
Do not drill them through the joists or rafters.
Even you are the first time to run security camera cabling you can install your security camera wiring through attics walls for your front back door reception room front back yard shop floor bedroom garage warehouse basement parking lot farm entrance even upstairs etc.