Yes, 18D provides safeguards, but as a letter to the editor I read today succinctly points out, the deterrent is not the legislation but the process.
Yes, you do need a significant resources to defend yourself against 18C. This has been proven by the students involved in the QUT case, where the student who didn't settle could face legal bills up to $500K should it go to trial (This was from last April, I haven't checked on how this case has progressed since)
It sounds like you are making an argument that the law should not exist because there is the potential to use the legal process to convince people to settle out of court.
This would be different to arguing that it should not exist for philosophical reasons (ie. it limits free speech or it provides to much protection for certain minorities).
I will point out that this argument could be applied to many of the civil laws. There is absolutely no evidence that 18C/D encourages this sort of behaviour more than any other law.
You may need significant resources to defend yourself against most civil suits. Unfortunately the law is complicated and the people trained in this area subsequently require compensation for their services.
The same argument applies to bring a civil suit against someone. You need resources.
There has been many claims of an abundance of frivolous legal cases in regards to many laws. As it follows I don't think that's a logical reason to change them, because at the end of the day those laws have actually protected people who have incurred real damages (ie. defamation, negligence, discrimination).
Section 18C and 18D have been around for about two decades now if I recall and to date there has been, if you look at the filings, no massive amount of successful judgments, and definitely not influx of frivolous law suits.
There is however a high profile media campaign based on one case in QLD at the moment. I think making arguments to change a law based on an isolated case are a bit rich.
I've already commented on this case (in this thread I think) but I will add that it's different to the Bill Leak case because it doesn't have to do with the defence of the performance or publication of an artistic work.
If you are so sure that the Bill Leak case is a no goer, then one would have expected a preliminary statement to have been made when the complaint was lodged, that prima facia no breach of 18C/D occurred. Instead all we got was The Race Discrimination Commissioner, Tim Soutphommasane, urging anyone who was offended by the cartoon to lodge a complaint under section 18C. One would expect The Race Discrimination Commissioner to know lodging such complaints would be fruitless and a waste of public and private expenses (assuming the complainant incurs costs other than time spent filling in the appropriate forms). Instead he urged others to also lodge complaints.
Again this is a different issue. This isn't an argument used to bring change the law, it's an opinion on how you think the Human Rights Commission should or should not operate and which cases they should or should not provide assistance or make a submission.