Hi Sidney,
Computers are making those trades for various reasons. For example, often when we transact our buys and sells we use a computer that trades automatically in line with the volume weighted average price (VWAP) for the day. It just means that our volume has less impact on the market because we’re trading very frequently in small sizes. I used to employ someone to do this manually for us, computers are much better at it and they don’t have sick days!
If Russia invades the Ukraine its like many geopolitical events i.e. a coin toss but when the allied forces invaded Iraq after falling for weeks the global equity markets enjoyed an aggressive relief rally i.e. “buy on rumour / sell on fact”.
Here’s the chart that Shane Oliver from AMP pulls out in every market sell-off as a reference point to keep calm and carry on.