The original question is more than 6 years old (but the lack of accepted answer makes the "Community" bot to randomly bring it on the front page, so you may have not noticed its age).
The OP was preparing a presentation on firewalls. Apparently he (rightly) feared that simply listing IPTables rules may not be attractive and concrete enough to keep his audience interest, so he wanted to find a more concrete way to demonstrate the actual effect and role of these rules.
He suggested in his question to use two computers, this would allow to show how a firewall rule allows to allow or block a connection. Some answer suggested to use Wireshark, which is both a simple and visual tool allowing to highlight the technical details.
In your answer, 6 years later, you suggested to use
ufw to generate the rules. IMHO, this suggestion doesn't seem to really fit the question. I don't see how this tool will allow the OP to better demonstrate the concrete firewall action to his audience. The OP problem was not about the rules, it was about how to demonstrate their concrete impact in a way he can communicate to his audience.
So, to sum-up, a new member comes and answer to a several years old question to promote a product which doesn't really answer to the OP request. I think that's why your post may have seem suspicious to the administrators.
Questions overtly asking for product recommendation are systematically closed as off-topic as they obsolete quickly.
Answers proposing a product are tolerated.
The best way to mention the product only to illustrate your explanation. Provide a factual and/or technical answer, explain how the OP question should be solved, the technologies / protocols / etc. involved. An then, at last, you can give a few examples of software implementing these ideas. You are even encouraged to present them with a critical point of view as far as the OP request is concerned.
For instance, on top of my head I remember an answer where I mentioned the tool SSLeuth which was very well received by the community. But if you look my post, it comes at the end of the post, merely as an example of possible approaches to solve the concerns raised in previous points.
Other than that, I recently encountered a border-line answer. It was posted by a new member, but on an active post, the author explicitly discloses his non-affiliation and his motives and the recommended tool may correspond to the OP request. His answer therefore did not fill the criterion to be considered as spam (but it still received a negative vote most probably due to the lack of content).
I hope you better understand now the distinction between post assumed as spam and post recommending or mentioning a software, and I hope this bad experience did not discourage you from posting other answers :) !