I have no problem with them. Sometimes there is good information in them that has not been discussed in a long while of since that thread started.
Also so there is a good chance that someone has a question about the topic as well.
When someone answers the OP’s question even though they haven’t posted in 2-3 years, the answer can still benefit others.
For these reasons I have read through plenty of necro threads.
On the other hand, I’m and glad that when the same questions are asked over and over ad nauseum folks will answer them rather than dismiss them by telling the OP’s to do a “search” like on many other forums.