Cruelty to animals is against the teachings of Islam. Those who do that are responsible. This does not mean that using any product is not allowed because the manufacturers did wrong as far as we don't support the wrong. There are two different issues in this question.
It is available in many supermarkets and shops especially in Madina and Macca.
You can also buy it online.
Yes it is allowed to use shampoos or lotions containing artificial alcohol.
Nothing is Najis unless and until you have concert evidence that it is Najis.
If you have doubt and want to be precautious, it is up to you to do Ehtiyaat (precaution) but we can not call any doubtful item as definitely Najis.