That issue seems to surface on this forum much more than on most as so many non-Lilium plants have 'lily' as part of their common name. Questions about daylilies (Hemerocallis), calla lilies (Zantedeschia), canna lilies (just Canna, but not a lily :-)) and toad lilies (Tricyrtis) are frequent. As well as peace lilies, rain lilies, naked ladies, peacock lilies, spider lilies, and Crinums.

while I answer the question if I can, I do point out the botanical name and direct them to the proper forum for any additional questions.

And I'm not at all sure it is an issue of thinking to be pretentious if using the botanical name but rather just an overall lack of knowledge about plant names.