You are not thinking.
Computers and algorithms do "about" 70% of all trading but it is not one entity but many, meaning they are not all trading the exact same way. They are not trading in conjunction with one another.
In addition, they do a lot of day and short-term trading which does not affect the mid and long-term of any one stock.
Nonetheless and generally speaking, they do trade much alike (meaning that chart and support levels are big keys for them). On the other side of the coin, one computer or one algorithm can give one support or resistance level more or less importance, depending on their programing. Programing is decided by the company and its tech traders individually, meaning that hedge fund A will have importance to one thing and hedge fund B will give different importance to the same thing.
Having said ALL of the above, knowledge is always valuable and knowing the basics of what computers and algorithms do is always a plus. With the information in your hands, you can then put in your own way of trading and your own information and come up with a plan that works best for you. If you do not use the information about how the computers and algorithms work and what are the basis levels that are important to them, you will find yourself among the people that don't have an edge over others and that usually means you will be among the losers.
You need to keep in mind that every single entity that is trading in the market is doing it for the profits involved and that means that for every single winner there has to be a loser. Do you want to have the edge and hopefully be among the winners, or the opposite.
By the way, you should be grateful that you are getting this information from me. It has taken me most of my lifetime (including a lot of bad times and losses) to learn this and I am giving this advice free to you. It is simple and general advice but it is knowledge that you probably will not get anywhere else.
Having said that, for this post of yours all I can say is that a lake is nearby and perhaps you should go and jump in it!!!