My take on it is a bit different. I think that in most years, there are 12-15 guys on the ballot who should go in, but each voter can only vote for a maximum of 10. So if you have a vote, you should vote for the best 10 on the ballot in a given year. So you could leave a guy off your ballot this year, because you think he's worthy, but there are 10 guys who are better, but then next year he's one of the top 10. Or vice-versa.
In Johnson's case, I don't see much chance that he wouldn't be one of the 10 best eligible players in his first year on the ballot.
You think there are 12-15 guys who should go in on every ballot?
That is the only reason, I think that a guy should be left off your ballot even if you think he belongs in the HOF - there are 10 other players that you think are more worthy. However, I don't think there's very many years that have 10 players that belong in the Hall.