You can easily form groups without group finder.
1. What is "easy" for one person can be difficult for someone else. Yes, if you have a lot of time to kill it is easy to spam the general chat looking for a group. If you only have a couple hours to dedicate, though, you need all that time for a raid, not spamming the chat hoping to get enough people together. A groupfinder queue could help in cutting down the time (unlikely since GF is usually long as is but it at least provides another option).
2. Part of the argument for a GF queue is to stop the endless spam of "LFG blah blah 8m SM" in general chat. I can hardly say anything on the republic fleet without it getting bounced up because of people looking for groups.
I am certainly all for adding Lvl 50 operations to the queue. I have cleared TFB several times and SnV a couple and have yet to do Karagga's Palace or Explosive Conflict at all simply because I don't want to spam general to find a group. I would prefer to do other things as I sit in GF queue, rather then waste time copying and pasting the same message. I don't think it would help people find groups faster, necessarily, but it would make the process simpler and allow people to enjoy other aspects of the game while waiting.