This should all be common sense really but unfortunately there are plenty of people using Steemit who try to use these 'tactics'. I assume most of them are very new here and don't have the patience to actually build their profile slowly over time by writing relevant comments/posts. I'm sure most will either get bored or realise that spammy comments won't get them anywhere and start using the platform properly.

I normally up vote comments on my posts as long as it seems the person has actually read the post and written something relevant even if it's just a sentence or two. The people who write "nice post" or "followed, follow me" are missing out.