So what is the problem here? Tooltip says you have -133 for relations with Austria because aggressive expansion.
It looks like it is year 1545. If you started in 1444 it means you have expanded (agressively) from 1 province to ~20 province in 100 years, inside HRE. Every province you take adds in, like every hostile action against neighbors, for example getting caught for fabricating claims.
http://www.eu4wiki.com/Agresive_expansion#Aggressive_expansion
AI in EU4 tends to make its mind about you by considering several things, like your military power, amount of provinces and so on. AE is very important factor here. How big a difference you make depends also of that who we are talking about. Ottomans don't probably care a lot, some nearby christian countries tend to think you are being bad and your neighbors are thinking there must be a way to kill of this mad brute. Small countries tend to team up in coalitions more often, if one of the neighbors starts to eat everything around it. That is how it is supposed to go.
Also since you are eating the provinces inside HRE you make the Emperor very angry by not respecting his authority and returning the things for their rightfull owners, if he ask nicely.