Because morality requires a lot of reflexion and empathy which both are absent from animals in a very significant way.
Both were once assumed to be absent in animals. Now we know it was a wrong assumption. There is very little that we have that other species do not. Larger brains is about all we have.
Everyone uses all their brain, if you are referring to the old claim that we only use 10%. It is not a good idea to make claims about brain use though when supporting communism.
I know that #LSD consumption activates large parts of the brain & that many people never use LSD so they miss out on this chance to grow consciousness: https://bit.ly/1qjEE1M
Yes, but you should look at more than just personal experience with pets. Pets are bred for specific traits. It is better to look at studies of other species.