using VPN will be the best option, to make it safe, paid VPN like ExpressVPN are better,
This is a little bit overkill for me. I only want to watch (not mine) bitcoin addresses on a public wifi (when bored) and I do not want the guy behind the wifi router to see what addressess I am looking at.
But your link lead to a link and that lead to a link and that lead to this source code
private static final ArrayList<BlockExplorer> prodnetExplorerClearEndpoints = new ArrayList<BlockExplorer>() {{
add(new BlockExplorer("BCI", "blockchain.info", "https://blockchain.info/address/", "https://blockchain.info/tx/", "https://blockchainbdgpzk.onion/address/", "https://blockchainbdgpzk.onion/tx/"));
add(new BlockExplorer("SBT", "smartbit", "https://www.smartbit.com.au/address/", "https://www.smartbit.com.au/tx/", null, null));
add(new BlockExplorer("BTL", "blockTrail", "https://www.blocktrail.com/BTC/address/", "https://www.blocktrail.com/BTC/tx/", null, null));
add(new BlockExplorer("BPY", "BitPay", "https://insight.bitpay.com/address/", "https://insight.bitpay.com/tx/", null, null));
add(new BlockExplorer("BEX", "blockExplorer", "http://blockexplorer.com/address/", "http://blockexplorer.com/tx/", null, null));
add(new BlockExplorer("BAC", "bitAccess", "https://search.bitaccess.ca/address/", "https://search.bitaccess.ca/tx/", null, null));
add(new BlockExplorer("BCY", "blockCypher", "https://live.blockcypher.com/btc/address/", "https://live.blockcypher.com/btc/tx/", null, null));
add(new BlockExplorer("BES", "bitEasy", "https://www.biteasy.com/blockchain/addresses/", "https://www.biteasy.com/blockchain/transactions/", null, null));
add(new BlockExplorer("CPM", "coinprism", "https://www.coinprism.info/address/", "https://www.coinprism.info/tx/", null, null));
add(new BlockExplorer("TBC", "TradeBlock", "https://tradeblock.com/blockchain/address/", "https://tradeblock.com/blockchain/tx/", null, null));
add(new BlockExplorer("BLC", "blockonomics.co", "https://www.blockonomics.co/#/search?q=", "https://www.blockonomics.co/api/tx?txid=", null, null));
}};
It seems that blockexplorer uses HTTP only, other block explorers use HTTPS. This is probably that "some encrypted some unencrypted" thing about the Electrum wallet and I suppose that this would be the case for all the programs unless they avoid blockeplorer what they definitely should.
using free VPN can create more risks than you can possibly think.
But a free VPN and a pain VPN from the same company is about the same risk, is not it?