The Church tried making paganism look like Christianity, in order to get the gentiles to join. For example: St. Brigid might never have existed, she may have been a Christian adaptation of a Celtic goddess.

All major holidays we celebrate these days are of Pagan origin.

many don't realize but Christians invented Christian holidays on these pagan holidays to attract believers. for instance Halloween which is considered pagan was actual a Christian day to celebrate the martyrs of Christianity. Christmas is celebrated off Jesus' birth and easter off the resurrection of him. yes these holidays are pagan holidays as well. but thats the effect of a flip side plan, of a strategic, but maybe not so successful attempt when early Christians tried to have celebrations on these days. i mean think about it. when would be the best day to spread the good news and try to win converts?

a national pagan holiday would be a good start.

Here are some wheel of the year celebrations and their christian counterparts:

Imbolc- Febuary feasts

Eoster- Easter Sunday

Bealtaine- Mayday

Samhain- All hallow's eve

Yuletide- Christmas

People should remember that these holidays were not originally christian.

While this is a valid argument, and I think only should be stated when the opposing debater claims originality, I don't find it worthy to mention otherwise. Pagans stole from other pagan religions, the abrahamic religions stole from the pagan religions and the neo-pagans stole from all of them. It seems to be normal and apparently not that big of a deal because symbols mean something to someone else. They'd just believe they have the correct version.