I would have no problem with cancelling all religious celebrations. Celebrating fantastical events like immaculate conception and rising from the death is just fucking bizarre. We don't celebrate an Alice in Wonderland day.
Birthdays are alright, but do they really matter, they only signify how the earth rotates around the sun and gives us numbers and an excuse to go and get pissed. It wouldn't bother me one bit if they were cancelled.
All “religious” festivals’ roots go back to the seasons and the Sun, or fertility or food. The fantastical elements came
much later.
Birthdays - pre-Christian, the day that celebrates individuals, especially those important to you like your family, show your appreciation for them while they’re alive (of course they matter!).
Valentines Day - pre-Christian and was about fertility, not a Saint. Fertility is important because without it, there’s no continuation of life.
Pancake Day - pre-Christian, they baked flat cakes to offer to their gods for thanks that Winter is coming to an end and Summer is on the way, the pancake signifies the Sun.
Lent - the word’s roots are from the old Northern European word for Spring (eg Lencten in Old English) or literally “lengthening of days” (Langitinaz in West Germanic).
Easter - the word literally means “where the Sun rises” and it goes back to proto-Indo-European language (ie
very old!). Related to the Vernal Equinox as that’s when the Sun rises at exactly 0° due-East. And not forgetting eggs and that link to fertility again.
Whitsun - taken as the birth of the Christian church and celebrated 7 weeks after Easter. The idea of celebrating a period of time after Easter/Vernal Equinox was the pre-Christian Cétshamhain (“first of Summer”) in the British Isles, halfway between the VEquinox and Summer Solstice or 6½ weeks after the VEquinox.
All Hallows/Saints’ Eve - Samhain (“last of Summer”), where the dead in your family are remembered and honoured, not Saints.
Harvest festivals - as old as the Neolithic Revolution itself. Celebration of food, “thanksgiving”(much older than the USA) to the Earth and the Sun for providing populations with that food that will keep them going through the Winter.
Christmas - Winter Solstice, the season of the end of one year and the start of another (festivities of this season start around 12 days before the Solstice with the earliest sunset of the year, to about 12 days after the solstice with the latest sunrise of the year), the birth/resurrection of the Sun, the evergreen symbolism in your home is again related to fertility.
As someone who spends a lot of time outdoors walking/hiking/running/cycling the seasons are important to me. I like the colder months because they’re refreshing (and I like the fashions!) but I’m always glad when the warmer weather returns. The importance of seasons still matters to people who work on the land and make their living outdoors, even gardeners find the changing of seasons important. Every time you put food in your mouth, when and where it’s grown is dependent on the seasons and the weather. But the history of this island and where it is latitudinally, it should be remembered about how hard and harsh the Winters would have been for the people who forged the history and identity of this island/these islands. It’s not about religion, it’s about astronomy, phenology, history and tradition.
Remove tradition and you remove culture. Remove culture and you’re left with dullness and lifelessness. It’s like removing the beautiful flower beds at Piccadilly Gardens and putting a big grey wall up in its place.