Because I find photoshop easier? And according to my knowledge you can't resize images in paint without distorting them.
Also, I didn't just get these images off google images... I had to take a SS, resize them, then paste them.
http://www.hc-sc.gc.ca/ewh-semt/alt_formats/hecs-sesc/pdf/occup-travail/whmis-simdut/faq/poster_symbols_e.pdf
Yes, I know, but you ignore 99% of the functionality Photoshop provides! You should try it.
That depends on the type of resizing you're doing. I've never used an image application that doesn't have the ability to resize something to smaller dimensions without distortion. I also don't know of any program that can resize a (normal) image to larger dimensions without distortion. Photoshop has something called vector images, which does allow for the resizing of a shape (ie a logo) without distortion, but that's strictly for developing the image or for reuse of that logo (maybe you want it to appear larger on a different document, but you don't want it to look distorted). When you're done, you convert the image to a distributable format, such as JPEG or PNG.
It's true that photoshop does have a bit more capability to reduce distortion, but that doesn't mean it totally prevents it! It does some antialiasing when you resize small picture into a bigger one, but if it's a very detailed (it doesn't take much detail!) picture, the effects of distortion are pretty noticeable.