It might be kinda difficult to know the exact reason(s) why your comment was downvoted because we do not know the person/people that downvoted it; only them can give their specific reasons. That being said..., As a rule of thumb, avoid making generic and uninformative comments as much as possible. You have the option to make quality informative comments (that's Relevance here), make no comment but act with your voting power (upvote/downvote) or just look away. "Do not beg for upvote please; doing so will only attract downvotes for you. Focus rather on making quality Relevant posts and comments and it will definitely attract upvotes." The quote above will be a better version of your comment, it stated why the person and others who will read it should not do what you said he/she shouldn't, it also gave an enlightenment about what should rather be done.