In a bull market, I think the TA may not work at some point, it follows certain behavior as the market reacts to the sentiments but TA does work in most cases when the market goes sideways or even in the bear market.
The only psychological in trading is controlling the trader's greed which is why most advice says don't be too emotional about it. Sometimes when a trader can't wait for the right price and just keeps buying and not knowing why, he'll end up losing.
Actually the working of a TA could actually be relative and this could have some kind of dependence on your strategy, there are strategy that helps you get to see more opportunities in the bull market much more than you would in the bear market but if you think you would always see opportunities with your TA then you are still gambling and not trading yet. The application of T A can actually work in both the bull and bear market depending on the trend and the opportunity you are looking out for based on your confluence of entries and your strategy to trade a particular trend or market.
Traders greed has got a whole lot to do with their psychology, if they could actually keep their psychology in check, they are very likely to be able to still trade profitably and cut down on their greed as greed at some point cannot be totally eliminated even amongst professional traders but discipline and proper trading psychology helps save the day.