The word 'luddite' often implies a critical view of someone's attitude toward technology. Calling someone a 'luddite' can be seen as an insult.
Pro Tip 2/3
Avoid Assumptions
A 'luddite' may actually be open to technology but worries about specific impacts. She's not a luddite, she just prioritizes privacy over convenience.
Pro Tip 3/3
Not Luddite Rebellion
Modern use of 'luddite' shouldn't be confused with the historical Luddite movement. He's a luddite in the sense he dislikes smartphones, not in the revolutionary way.