Yes, if you share values with someone or respect someone's work, you might be genuinely interested in where and why they post stuff somewhere else like on Hive frontends. While on Reddit, people don't pay much attention to usernames and their content - people focus on subreddits. (But Reddit is amazing for other reasons).
to build there something and support them each other
Some engagement from the fellow Hivers, even a simple "this!" (or a good argument for the opposite opinion), might really boost a nice post. Threads even sometimes shows a post and the most popular comment below it right in the feed - a good bonus for nice commenters.