Tea is difficult; thc is not water soluble, so you would need to add it to something else so that it can dissolve. It is, however, soluble and commonly dissolved in butter/milkfat, peanut oil, alcohol, and vegetable glycerine. It also has to be heated high enough and long enough to activate it (decarboxylate), or else it won't have any effect. A lot of baked goods don't get hot enough for long enough to active it all, and they also cook unevenly, and consequently you can get very inconsistent dosage (typically you would want to decarb before baking, but overheating can cause THC to break down as well).
Personally, I say everyone should just vape it. Doesn't smell nearly as much or as bad, and it is significantly less unhealthy.
Summum ius, summa iniuria.