Protein powders are safe to consume in moderation.
I drink protein powder every few days myself and it's been no problem but when you do drink too much protein powder and drink protein powder in excess then it can cause health issues.
The main problem when drinking too much protein powder is that it can cause health issues and can lead to an increased risk of developing osteoporosis and can also worsen existing kidney problems.
Kidney disease can also occur when drinking too much protein powder but when you drink protein powder in moderation they are very safe.
Just like any other drinks and foods too much can be a problem but in moderation they are healthy and the protein powder can help you build muscle when you need to build muscle or want to build muscle.
But just don't overdo it.