I don’t know if I should feel flattered or offended

IMHO if someone pays attention to you, then you should feel flattered, not offended:

I was contacted via a message sent with Gmail by a person claiming to be responsible…

There are 4 key values that we find important when traveling: improving our environmental impact, deeper personal experiences, more meaningful social relations, and supporting the local economy – Less Travel

Yet, I do admit that being stalked, doxed, or anything like that feels more like an invasion of personal privacy… well, I guess that could indeed be considered offensive.