I've seen one too many rants about various habits of modern reconstructionist pagans (pick one, there are dozens to choose from) that boil down to, "If it's not attested in the lore, you're a bad pagan for doing it." Maybe it's because I'm working in a tradition where I know we didn't get all of our details written down and had much of what was transcribed hopelessly altered, but that argument annoys the living daylights out of me. Why? Simply put, the lore is fallible.
Those of us on reconstructionist paths are participants in interrupted or modified traditions transcribed by imperfect beings with their own agendas. None of us approach them as tabulae rasa, either. Also, it's the rare modern pagan who's a participant in the descendant of the culture in which the lore arose. Those themselves have changed despite all attempts within the culture to the contrary. And during the life of that culture before whatever break occurred, the lore itself changed. If it didn't, we'd all still be consulting tribal shamans to figure out which spirit to appease to cure our migraines.
The fact our ancestors of blood and spirit changed with their times, however willingly, tells me that if we don't admit the lore isn't the end-all and be-all of what we do, we're failing as inheritors. It's not right to declare our modern inspiration or language usage to be identical to what they did. But it's also not right to insist we restrict ourselves to some fantastic concept of static, unchanging belief they themselves didn't follow. Within Celtic tradition, there is lingering evidence of gods rising and falling in popularity. We know the Germanic pagans altered their approach to Wodan when exposed to the Danubian Celts' worship of Lugus. And how much more so would the gods and traditions of our ancestors shift and change with the technological and theological innovations in the intervening centuries? We can't even begin to guess. But change they would.
I fail to understand why some pagans want to treat their written lore as being the perfect transmission while laughing at the Christians who think their lore is equally inviolate. It's just as ridiculous to claim Snorri transcribed a perfect record of how all Norsemen practiced their beliefs as it is for Christians to claim the Earth was created in six days. The lore is a base, not a stopping point. Using it as a means of bashing people who speak in a way you find inappropriate is fundamentalist thinking. If someone else's modern approach is labeled as such, as my late grandmother would say, kwitcherbitchin'. Nobody's forcing you to join in on it.