Opinion based posts are those that cannot be rationalized with either logic or references. We cannot have vague discussions; it is impossible to contain them. If a topic is precise then it should have a defined answer.
If users are not willing to use the chat for discussions then they perhaps are not interested at all.
In addition to the answer from @WYSIWYG; the entire StackExchange network generally discourage opinion-based questions and discussions (see e.g. this and this post at meta.stackexchange.com). StackExchange sites are not discussion forums but places to ask and answer specific questions. If you want to have open-ended discussions you should choose another ...