The logic for investment is buying low and selling high and currently Bitcoin has a new ATHs is it safe to encourage new investor to buy now seeing how high the price has gone? My fear for new investors is that the don't experience a dip after buying since no one is sure of how far the new highs will reach.
It's never 100% safe to buy. People encourage newcomers to buy, because they don't care if they can experience a loss or not. But if you tell people to buy and HODL, then you can do it at any time, because they will make profit in the long run if they don't panic sell.