However, this is purely specious reasoning used as an excuse to participate in customs which are truly pagan celebrations with all the trimmings.
The calendar currently used by the Watchtower Society is the Gregorian calendar. This calendar is named in honour of Pope Gregory XIII. Its months are named in honour of the pagan Roman kings/gods Augustus (August), and Julius (July) as well as having months named in honour of Roman and Greek gods and goddesses such as Janus (January), Mars (March), Maia (May), Juno (June), and a pagan ritual- "febura" (February).
And some of the days of the week are named for Norse gods (and others): Woden's Day; Thor's Day; Freya's Day - but it is obtuse to think that, although these names are involved, that we are honoring these pagan gods by using the common day and month designations for our society. We have no practical option but to use them.
But as for customs which are devoted to honoring these gods, we do have a choice and, according to Scripture, we should take advantage of that choice.
There are many things which originated, necessarily, under paganism. Pharmacies, Doctors, and who knows what all, but that doesn't make these necessary things a celebration of pagan gods. What is being spoken to by Jehovah's Witnesses is the participation of Christendom in paganistic customs and celebrations which were deliberately borrowed by the Church from pagan celebrations and ceremonies honoring their gods.
There simply is no honest comparison between using necessary information such as the universal use of pagan names for days, months, cities, personal names, etc. with the personal CHOICE to celebrate completely nonessential pagan celebrations.
The early Christians didn't see the need to use their own alternate names for (nor to avoid going to) cities and places which had pagan-related names, nor using the paganistic personal names of individuals. (See Luke and Paul's examples below.) There is a place for reasonable avoidance of actual customs and celebrations devoted to pagan gods and the everyday use of common words.
It is the use of pagan things associated with pagan worship that is at the heart of the issue. It would be wrong to incorporate anything used for pagan worship, into our worship or related activities. Holidays, for example, are "Holy Days" and are a part of "worship", by their very name. The mere reference to a day or month on a calendar is not.
The mere reference to a day or month on a calendar cannot possibly be equated to the making of unusual efforts to participate in customs with known pagan origins (like celebrating holidays).
For biblical examples, when Luke wrote in Acts mentioning the Areopagus ('Ares Hill' - Ares is the Greek god of war; 'Mars' is the Latin god of war), he didn't feel the need to change its already established name to something no one would recognize. Furthermore, Paul actually went to this place devoted to a pagan god and preached.
And Paul accepted the Areopagite, Dionysius (Greek name for 'god of wine') and had him join him - Acts 17:19-34. Luke and Paul certainly did not become participants in something associated with pagan origins.
The following article is taken from the 5/15/67 Watchtower, Questions from Readers:
"Why did the Jews use the name of the pagan god Tammuz as the name for one of their months?
"Tammuz was the name of a Babylonian deity. (Ezek. 8:14) And though the Bible does not apply the name in this way, postexilic works, such as the Jewish Talmud, use the name for the fourth Jewish lunar month of the sacred calendar, the tenth of the secular calendar. (Ezek. 1:1) So it would correspond to the latter part of June and the first part of July.
"The use of the pagan name Tammuz as applying to the fourth month of the sacred calendar may have been only a matter of convenience among the Jews. We should remember that they were then a subjugated people, obliged to deal with and report to the foreign powers dominating them. So it is understandable that they might utilize the names of the months employed by these foreign powers. Similarly, the Gregorian calendar used today has months named after the gods Janus, Mars and Juno, as well as for Julius and Augustus Caesar. Yet it continues to be used by Christians who are subject to the "superior authorities." - Rom. 13:1." (Emphasis mine.)