Human words are a great deal fuzzier than the concepts they hope to cover. For instance, consider the word "love"; it means anything from stalker-level obsession to a moderate preferance ("I love pizza!"). In order to talk about anything precisely it is often necessary to specify what a given word refers to in some specific context.
Every writer has the right to choose what definitions they are using in a particular bit of text. If they say that they have chosen a particular definition of "love", that is not a point that can be usefully debated. Definitions are neither right nor wrong. They are only useful or not useful. What can be debated is statement the word is used to make.
In principle, one could have two people debating with each other, each choosing a very different definition of love. There is nothing wrong or illogical about this, except that it may be confusing.
This is my generic disclaimer I offer when choosing a definition:
- I am not saying this is the only definition. (If that were the case, I would have had no need to be clear in the first place.)
- When I've chosen a particular definition and then start talking about it, I have done so precisely because there are conventional meanings of the word for which my statements do not apply. If that were not the case, I would not have had to be specific. If I choose to talk about "stalker love", then I say "Love is evil", clearly I'm not claiming all love is evil.
- I am not saying you must use this definition for any purpose. Those if you wish to disagree directly when I've used a definition, it would be somewhat simpler to use the same one as me if you can, and failing that, important to be clear about your own use of the term lest everyone become confused.