I don't see tallow as a "waste" product, as I don't see the need to kill the animal for food in the first place, but this is a whole different topic and story though and would be digressing from the topic of this thread again.
You are right though, that palm oil prodction in certain areas kills endangered Orangutans and in most cases you don't know the origin of that ingredient. Some manufactures are also aware of that issue and use palm oil from certified and sustainable sources, like Columbia.
Wickham soaps, as an example, state on their webseite:
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Palm Oil* – Elaies Guineensis
Sustainably certified palm oil produces a sumptuous, long-lasting soap with a thick, creamy lather. Gentle on all skin types, palm oil is loaded with Vitamin E and delivers exceptional moisturising and conditioning results.
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*The Importance of Sustainable Palm Oil
From Malaysia to Colombia to West Africa, the palm tree is found all across the equatorial regions of the world. Palm oil is produced from the flesh of the palm fruit and is highly saturated due to its palmitic acid content. Palm oil is a popular choice for soap makers as it saponifies easily due to its high Vitamin E content. Recently, there have been huge concerns about the devastating effect palm plantations are having on ancient forests and endangered species. The Roundtable for Sustainable Palm Oil organisation formed in 2004 to help combat the effects of this unsustainable project. The organic palm oil I use is sourced from sustainable, eco-friendly crop plantations in Columbia which are signed up to RSPO. For more information on this initiative, please visit www.rspo.org.
Nanny's Silly Soap:
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All Palm oil used produced by Roundtable on Sustainable Palm Oil growers and is also organic.
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Nearly all my products are suitable for vegans; all stearic acid and glycerine used is of vegetable origin.
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The soap, that I use in the shower also uses palm oil from similar sources.
But yes, palm oil production is an important point. In some cases, you just don't know as a consumer. It is the same with stearic acid or glycerin, which can be plant or animal based. Sometimes even the soap manufacturer does not know, where the ingredients come from. It is the case of "ignorance being bliss" again.
All you can do as a customer is trying to educate yourself, try to find out what materials and ingredients are used and make an educated decission to either use a certain product, even if there are some unknown factors involved or choose a different product.
In my opinion, that beats knowing about certain issues and problems and doing nothing, just because it is more convenient.
Can we just get back to the topic, as I hopefully answered your question?