"I am also puzzled as to what the moderators consider to be personal insults."

As are they many times. "Personal" insults are not always clear & unambiguous. It is often a matter of context & past history.... but that is only one problem.

" Can we not have some guidance as to what is acceptable and what is not and then have consistency in deleting posts that are unacceptable and suspending or banning those who regularly break the rules? "

Dave... you have been here long enough to remember when they tried to follow a consistent set of rules and keep up with the various threads. What did it get them? It got even more complaints about whether they had been fair & reasonable.... and when stuff was edited or deleted, it often led to bewilderment about broken continuity as folks tried to guess what HAD been deleted.
   Joe Offer has explained all this several times, and Jeri & SRS have tried to clarify it. Max said years ago...(paraphrasing) "It is up to the members, mostly, to learn to converse and make the forum comfortable." But humans come in way too many flavors to write simple guidelines... some want restrained, friendly discussions, some relish unrestrained battle.."Ooh, threats! Great! let's have it then. " (It wasn't a threat... it was my way of refusing to engage in a type of argument that I do not practice regularly, and which 'others' are far better at. Cultural differences...etc. ☺)

I have opinions... and I have stated them on many, many topics for many years here. But I **CHOOSE** to debate the issue and NOT get into a mud-slinging fight with those who disagree with me.
(and there I go, resorting to ".. the quotes, the asterisks and the capitals... " again.)
   Sorry Steve, but that's how I **CHOOSE** to try to make my typing sound like I was talking. It is not up to you to correct my typography...or to direct how I phrase my occasional debate with Pete. If all you want is to bait me into a freewheeling insult match... at which you'd win hands down... no thanks.
(I just remembered a story about our former president, Calvin Coolidge, who was known as "Silent Cal" for his terse and restrained style. A matron came up to him at some event and burbled, "Oh Mr. President! I've just made a bet with my friend that I could get to say three words to me!"... Coolidge looked at her calmly and said , "You lose.")

I, obviously, am not as clever OR restrained as Coolidge, but I do keep his example in mind at times.