So pre 7.0, the tutorials were broken, meaning there was no guidance at all through the bot matches. This meant they were no different from playing solo matches against bots. so, what was the point of restricting the hero selection?

NOW... after 7.0 the bot matches are completely 100% broken. You get spawned into a bot match with no bots!!.... all you can do is run around hitting creeps... which is less useful than demoing the hero from the hero select screen.
It's been like this since 7.0 hit... and there have been many threads about it on various forums.... including here.

The odd thing is... I just logged into steam to see the DotA feature on the store front page. So valve are now trying to entice new players into their game by inviting them to play a release build that is totally inaccessible to beginners. !!
The world has gone mad!

I'm trying to get into the game... and without trawling through 3rd party videos on youtube... you have no chance. If the first time I'd of logged in I was faced with a tutorial that didn't work... for a game that has a notoriously steep difficulty curve... I'd of just given up on it.