do note that even if there is someone managing to reach > 50%, they still cannot just do anything. You can ignore certain transactions, make sure they are not inside a block, therefore disrupting bitcoin, but there are limits to what you can do, and you certainly cannot just create money or steal from someone else.
Also note that even if a pool reaches >50%, they still need to abuse their power, which will be detected and people will be warned... it's not something you can do in secret. Also note that >50% gives you a theoretical advantage, if you want to abuse your power,you can do so also with for example 10%, you will just have a lower successrate.
However, if a pool is really abusive and has 50% of the hashrate, one cannot stop them due to lack of power. So yes, it is good to make sure nobody ever reaches 50%.
There are many good smaller pools out there, if you want to support bitcoin, make sure you get to a smaller pool