It's not cruel at all..

alot of people have this idea that cats are roaming animals and should be aloud to do so.. even in the modern world with cars and not so pleasant people about....

dogs and horses naturally have always freely roamed but seem to adapt well to having boundries..

I have 2 indoor cats who have scratch posts, toys and loads of attention and they are thriving..

If you want to keep your cat indoors safe from the busy road then do so, and dont let any one tell you otherwise