You have to turn the sentence around to see if it makes sense and is singular or plural. In this case it would be as follows: “A lot of rumors are flying there on this thread”, so I would say it is correct to say “There are a lot of rumors flying on this thread”. It would not sound right to say “A lot of rumors is flying there on this thread”. In other words, take the sentence apart and just use the subject and verb and you have “rumors are flying”, not “rumors is flying”.
Have I made myself clear? There will be a quiz on this.
He may be referring to the fact “a lot” was used in there. “A lot” is a singular.
Of course, we could cry “BRITISH!” and use the abuse of “the enemy have” and “the enemy are” as rationalizations for saying “are a lot”.
“There are a lot of rumors”
“are” is acting on “lot” and not on “rumors”, since “of” makes “of rumors” an effective adjective on the word “lot”.
Since “lot” is a singular word (plural would be “lots”), “there is a lot of rumors” is appropriate, or “there are lots of rumors”, if you want to use “are”.
“There are a lot of rumors” is therefore incorrect.
Your Majesty made Themselves absolutely clear.
But. (”The nature of thinking is but” - Susan Sontag)
We are talking about one lot, no? A lot, not ten lots.
“There is one lot of rumours”, not “There are one lot of rumours”.
There are lots of rumours, yes. There are many rumours, not there is many rumours.
Have I made myself unclear?