This can be blamed entirely on its physical structure, anonymous. Linoone’s body is long and thin, and its legs are extremely short. Both of these in combination make maneuvering at high speeds extremely difficult; if it tries to turn, it runs a risk of tripping over itself or otherwise injuring itself in the effort. So instead, it picks the easiest direction to run in, which just happens to be straight.
As for your other question, that depends on the linoone. Some will stop and turn, others will stop and lash out at you for bothering them, and a small percentage (of not terribly bright linoone that are trying their best nonetheless) will keep on running in the direction that you’ve chosen for them.
Which is to say, please don’t nudge your linoone.