What the Society's angle is on bringing up 1925 I do not know
In line with what diamondiiz said, I think it makes a misleading statement technically true.
This statement would be a blatant lie:
"Since 1925, Jehovah's Witnesses have recognized that World War I and the events that followed amount to sure evidence that Christ's presence began in 1914"
But this statment is technically true because of the qualifier:
"Since 1925, Jehovah's Witnesses have recognized that World War I and the events that followed amount to sure evidence that Christ's presence in heavenly kingdom power began in 1914"
It's not quite a claim that JW's in 1925 recognized that Christ's presence began in 1914 even though many JW's will probably understand it that way. It's a claim that since 1925 JW's have recognized that the invisibly present Christ attained "heavenly kingdom power" (Whatever that is..) in 1914.
In the year 1920, the crowning of Jesus as king of God's kingdom was moved from 1878 to 1914 (cf. The Watch Tower July 1, 1920 p. 196) In the year 1922, the significance of 1914 was explained to mean that God'd kingdom had been invisibly set up in the heavens. (cf. The Watch Tower November 1, 1922 pp. 332-337) And in 1925, Revelation 12 was specifically applied to this event. --Christ took his power to reign, outsted Satan from heaven and God's heavenly kingdom was born in 1914 with Christ as king.