user behavior – Why is the "do not like" button being endangered?

In addition to JohnGB and Jimmy's answers, I would add that not having a negative vote button potentially generates more content and, in particular, can generate content representing alternative views.

For example, if someone starts a thread saying "We should ban any soft drink" and you feel the need to act with this thread, you can not just press the "negative vote" button . You really need to express your ideas in words, explaining why you think it's a bad idea, and publish that content on the website.

In the end, for this example, you can get +9 positive votes and the PO, +6, and you can both feel comfortable about it rather than not getting any votes at all, and less content is generated for use by other users.