I saw a lot of online shops say "We have banned/discontinued use of this product. For informational purposes, we have posted the link to Thuja."
Many oils, if diluted in carrier oils like olive oil, have toxic effects minimized. It may or may not be suitable for children, and definitely should not be used by pregnant women under any circumstances if there is any hint of toxicity or uterine contractions.
Some aromatherapists are merely massage therapists, some are are herbalists. I would hope that the ones that studied all the oils for their medicinal value would know which ones are harmful to certain types of people and know the contraindications, like: avoid if pregnant, known for photo-toxicity, do not use if you have high blood pressure, do not use if you have seizure disorder, not safe for infants under 12 months, etc. Those are very basic standards, I would say
Anyway, natural stuff can be potent and isn't safe all the time. I think that's why mainstream products are so widely accepted and there's usually smaller chances of massive side effects or allergies.
I know somebody will blast me for saying that, but it's the reason why mainstream products were created -- for the convenience of use and for general safety.