As with everything in life, don´t do something unless you know what you are doing. If you are uncomfortable about modding and mods "breaking" your game - don´t do it! Learn about it first! But stop mis spreading information.
FYI, games cannot be "broken" permanently in Steam - it takes literally a couple of seconds and a few clicks to set the game files back to "factory files". It´s a fully reversible process: if you see that a mod did "break" something, it´s just temporary. Again, it takes a couple of seconds and a few clicks to restore your game files. Thank you Steam.
Using mods, or not using them, is a totally personal choice. It´s also a personal choice to use only the ones you want. I, for instance, only use the ones I´m interested in. The ones I´m not interested in, I don´t use. I won´t use mods I don´t "understand" either - i.e. I need to understand how the mod is created and how the mod is implemented. I don´t need to know exactly each step, but I need to understand the reasoning behind how the mod was created and how it is implemented in-game.
At the end of the day, we all know that Frontier is not able, capable or enthusiastic enough to deliver all animal biodiversity. Some users might be happy with that. And that´s totally fin and I totally respect that. Others are so enthusiastic and passionate about the game that they actually want to build the "zoo of their dreams", and this is based on diversity and with hand-picked, curated, animals. I want a black ruffed lemur, a Sumatran tiger and a Masai giraffe. Frontier won´t deliver them, but the mods will - eventually. And that´s why I am totally supportive of the modding community. Will I stop supporting Frontier Planet Zoo development and buying DLC? No - I will carry on doing what I´ve done from the beginning.
If you play Planet Zoo as a building and landscaping simulator, then you probably won´t care that much whether it´s a Masai giraffe or reticulated giraffe. But if you are passionate about zoo´s and biodiversity, then, you do care. And that´s why, IMHO, the steps achieved by the modding community are paramount to expand biodiversity within Planet Zoo.