OK, here' a definitive at home test to confirm whether a fork is straight or bent to one side. You'll need a table, a tri-square or ruler, some books, and a friend or two.

Start by removing the bars and/or the stem, then add spacers so the headset can be adjusted. Stack up books or something similar on the table to about 3 inches or so. Make a few stacks to support the top and down tube with the cranks clear, (or remove a pedal) or support the top and down tube and rear triangle. In short you're trying to float the frame over the table roughly parallel however you can. Have your friend(s) press the frame down and hold it firmly in place.

Using the square, rotate the fork so both tips touch, and note the height of the lower one. Rotate the fork 180° and repeat the measurement, and compare. It's important that the frame is held steady through this operation, so you might want to repeat a few times. If the measurements aren't equal or within 1-2mms the fork is off. Otherwise look elsewhere for your handling problem.

BTW- even a bike with a pretty bent fork can be ridden no hands, it simply calls for tilting the frame to compensate.